Nufarm Ltd v Jurox Pty Ltd [2008] FCA 178 (29 February 2008)

Last Updated: 4 March 2008

FEDERAL COURT OF AUSTRALIA

Nufarm Ltd v Jurox Pty Ltd [2008] FCA 178

PATENTS - alleged infringement of oral sheep drench patent - construction of patent claims - where language of claim is ambiguous - patent specification and claims must be read together and in light of common general knowledge and art before priority date - where skilled addressees disagree as to meaning of technical words in claims and whether certain examples given in specification are covered by patent - subjective intention of patent author irrelevant - whether a particular skilled addressee's knowledge of prior art is 'idiosyncratic'



Patents Act 1990 (Cth), s 13

Décor Corp Pty Ltd v Dart Industries Inc (1988) 13 IPR 385 cited
Kimberly-Clark Australia Pty Ltd v Arico Trading International Pty Ltd [2001] HCA 8; (2001) 207 CLR 1 followed
Kirin-Amgen Inc v Hoechst Marion Roussel Ltd (2004) 64 IPR 444 cited
Populin v HB Nominees Pty Ltd (1982) 41 ALR 471 followed
Root Quality Pty Ltd v Root Control Technologies Pty Ltd (2000) 49 IPR 225 cited
Sachtler GMBH & Co KG v RE Miller Pty Ltd (2005) 221 ALR 373 cited
Sartas No 1 Pty Ltd v Koukourou & Partners Pty Ltd (1994) 30 IPR 479 cited
Synthetic Turf Development Pty Limited v Sports Technology International Pty Limited (2005) 67 IPR 475 cited









NUFARM LIMITED (ACN 091 323 312) AND ARGENTA MANUFACTURING LIMITED v JUROX PTY LIMITED (ACN 000 932 230)
VID 746 OF 2004

MIDDLETON J
29 FEBRUARY 2008
MELBOURNE

IN THE FEDERAL COURT OF AUSTRALIA
VICTORIA DISTRICT REGISTRY	VID 746 OF 2004

BETWEEN:	NUFARM LIMITED (ACN 091 323 312) First Applicant ARGENTA MANUFACTURING LIMITED Second Applicant
AND:	JUROX PTY LIMITED (ACN 000 932 230) Respondent

JUDGE:	MIDDLETON J
DATE OF ORDER:	29 FEBRUARY 2008
WHERE MADE:	MELBOURNE

THE COURT ORDERS THAT:

The parties confer and thereafter each file and serve short minutes of final orders reflecting the reasons in the judgment handed down this day, including orders as to costs, within 14 days.

IN THE FEDERAL COURT OF AUSTRALIA
VICTORIA DISTRICT REGISTRY	VID 746 OF 2004

BETWEEN:	NUFARM LIMITED (ACN 091 323 312) First Applicant ARGENTA MANUFACTURING LIMITED Second Applicant
AND:	JUROX PTY LIMITED (ACN 000 932 230) Respondent

JUDGE:	MIDDLETON J
DATE:	29 FEBRUARY 2008
PLACE:	MELBOURNE

REASONS FOR JUDGMENT

INTRODUCTION

1 This proceeding is concerned with the alleged infringement of Australian Innovation Patent No 2003101020 (‘the patent’) by Jurox Pty Limited (‘Jurox’).

2 The registered proprietor of the patent, as at the commencement of the proceedings, was Nufarm Limited (‘Nufarm’). However, Nufarm has since sold the Health and Sciences division of its business to Argenta Manufacturing Limited (‘Argenta’). As part of that sale, Nufarm assigned the patent to Argenta by a deed made on 7 February 2007. The registered proprietor of the patent is now Argenta, who was added as a second applicant to the proceeding on the first day of the hearing.

3 Until Nufarm sold its Health and Sciences division, it was in competition with Jurox. Both Nufarm and Jurox carried on the business of manufacturing and supplying, amongst other things, veterinary compositions to the Australian market.

4 The invention described and claimed in the patent relates to a stable, veterinary composition which is used principally as an oral drench for the purpose of controlling intestinal parasites (worms) which infest, primarily, sheep.

5 The invention the subject of the patent relates to stable veterinary compositions containing a mixture of active ingredients, combined into a single formulation, and its use for the treatment, eradication and control of a disease known as helminthiasis that affects certain warm-blooded animals. The invention also includes a method claim, which involves oral administration to the animal of an effective amount of the stable veterinary compositions described.

6 The priority date of the patent is 4 June 1999. As at that time, it was known that certain endoparasitical compounds, called anthelmintics, were known to eradicate or control endoparasites. The specific endoparasites targeted by this invention are nematodes (otherwise known as roundworms), cestodes (otherwise known as tapeworms) and trematodes (otherwise known as flukes).

7 It was also known that certain endoparasitical compounds are active against certain endoparasites, and not others. For example, macrocyclic lactones (such as ivermectins) are active against nematodes and also against some ectoparasites (non-intestinal parasites, such as ticks), yet they are inactive against some important trematodes which affect sheep. Levamisole products are active against nematodes but are ineffective against tapeworms, liverfluke or worm eggs. Some benzimidazole products have a broad spectrum of activity against endoparasites, while others do not.

8 Further, it was known that using only an individual active to treat helminthiasis promoted a resistance problem, which reduces the efficacy of that particular active.

9 It seems that there were a number of practical difficulties in producing commercially attractive and practically effective formulations. The relevant considerations included:

• The desirability to administer treatment as infrequently as possible;

• The variability and spectrum of activity of individual anthelmintics; and

• The reduction in the efficacy of using individual actives to treat and control the disease, due to a developed resistance to its effects.

10 Accordingly, the prior art included several formulations involving two or more active ingredients, aimed at increasing effectiveness and preventing the resistance problem. However, such combination formulations were found to be extremely poor because they suffered both chemical and physical instability. The incompatibility of different actives led to instability and degradation.

11 One such product was by Amcare, which contained two actives, being levamisole and another. However, it was found that if that product was contaminated by water, it was too viscous to use. Amcare then tried a detergent based mixture of those two active ingredients, but apparently that product was not safe, and could not easily be used as an oral drench.

12 Another prior art formulation used two active ingredients: levamisole and a benzimidazole. However, apparently due to the different levels of pH required to maintain the stability of the individual actives, it was found to be unstable, at least unacceptably so. It seems that the pH levels caused the product to degrade.

13 Further, in some combined products, when left standing, the active ingredients would separate out, such as the levamisole rising to the top and the benzimidazole descending. This would lead to an increased risk of overdosing or underdosing.

14 Another four New Zealand patents were referred to as part of the prior art, which included:

• A transdermal formulation (administered by pouring on the animal) with a single active ingredient in vegetable oil;

• An oral drench with two or more active ingredients; and

• Two injectable formulations with two active ingredients, and benzyl alcohol and some vegetable oil.

15 These formulations are described in the patent as having extremely poor chemical and physical stability. Further, the pH levels were not conducive to long term stability. The acidity levels caused the overall liquid environment to lose efficacy over time.

16 Against the background of the prior art, and the problems associated with treating helminths, one of the stated objectives in the patent is as follows:

Accordingly, it is an object of the present invention to provide veterinary compositions having anthelmintic activity, comprising at least one macrocyclic lactone, levamisole and at least one benzimidazole, and where the compositions are both chemically and physically stable.

17 The invention does not create a new molecule, but can be described as a novel delivery system, employing known compounds of known biological activity.

THE PATENT

18 The patent is entitled ‘Stable Biocidal Compositions’. The specification recites that:

The present invention relates to stable veterinary compositions and their use to treat, eradicate and/or control helminthiasis which is a disease that affects warm-blooded animals in particular cattle, sheep, goats and other domesticated herbivores.

19 The claimed invention contains two distinct aspects. One is the various compositions of the active ingredients, and is described in the following terms:

In one aspect of the present invention there is provided a storage stable veterinary composition for oral administration comprising:

(i) at least one avermectin as a first active ingredient;

(ii) at least one organic liquid carrier which carries at least most of said first active ingredient to define an organic liquid phase;

(iii) levamisole as a second active ingredient;

(iv) at least one benzimidazole as a third ingredient; and

(v) at least water which carries at least most of said second and third active ingredients to define an aqueous phase;

wherein said aqueous phase has a pH of less than 7 and includes an emulsifying agent(s);

wherein said avermectin is abamectin or ivermectin; and

wherein said aqueous and organic liquid phases exist in, or can be shaken or agitated into, the form of an emulsion with any particulate content if any, being at least substantially present in said aqueous phase.

20 The second aspect is a method claim, described as follows:

In a second aspect of the present invention there is provided a method of treating helminthiasis in a warm-blooded animal which method comprises orally administering to said animal an effective amount of the stable veterinary composition of the first aspect.

21 The method claim is not a substantial issue in the proceeding, and is really a subsidiary to the primary claim, which is the actual chemical formulation.

22 It is useful to develop the meaning of stability in the context of the specification. The body of the specification recites:

As used herein the term "chemically stable" means that the active ingredients, within +/-10% w/w of their stated composition, are preferably stable for at least 3 months, more preferably at least 18 months when stored at 25deg.C or below and at ambient humidity. Further, as used herein the term "physically stable" means that the composition of the invention is substantially homogeneous (despite any optional particulate inclusion(s)) and/or can be readily agitated to form a substantially homogeneous state.

23 The body of the specification also discusses two chemical environments to separate the different active ingredients as follows:

The organic liquid carrier is preferably selected from the group consisting of one or more oils; emollient esters; an alcohol having multiple carbons; diols and glycol esters. In a more preferred aspect at least one organic liquid carrier is an oil, preferably a mineral or vegetable oil or a co-solvent such as benzyl alcohol.

Preferably there is present in said aqueous phase a particulate content which is either an active agent or an inert substance. In a more preferred aspect the particulate active agent is a biocide.

In another preferred aspect the aqueous phase has a pH of less than 6, more preferably a pH of less than 5 and even more preferably a pH of less than 4. Preferably the aqueous phase also includes a buffering system to buffer the pH. In a more preferred aspect the buffering system is a citric acid/citrate salt system.

Preferably the composition of the invention includes in one or other, or both, of the partitioned phases one or more of the group comprising minerals and vitamins.

24 The specification also recites that in yet another preferred aspect ‘the stable veterinary composition is in the form of an emulsion’.

25 The specification also states:

In another preferred aspect the invention is a stable veterinary composition comprising about 0.08% ivermectin, about 3% levamisole, and about 2% albendazole where different liquid carrier phases substantially partition the ivermectin from the levamisole, and where the albendazole is particulate and is at least in part in an aqueous phase with the levamisole, such aqueous phase being buffered to a pH appropriate for the levamisole and its stability, and where the ivermectin is substantially in an organic phase.

26 The specification explains that water insoluble active is dissolved in the oil, which is emulsified in water. The oil protects the active against the pH or constituents present in the water phase.

27 A number of examples are described in the specification, which are claimed to illustrate the invention in more detail. Importantly, the specification states:

These examples show various formulations directed to a resistance strategy which nevertheless are stable and may have additional therapeutic and/or active inclusions. It should be understood that the present invention is not construed as being limited to these Examples.

28 There is some commentary on the effectiveness of the different examples.

29 Example 1 consisted of a combination formulation of abamectin and levamisole and a number of additional ingredients. The specification states that the formulation was ‘too thin’ and examples 2 to 4 were thickened Carbopol or gums. The following examples 2 to 4 included the thickening agents at varying concentrations. The specification states that the pH level of these formulations was too low for the long-term stability of abamectin.

30 The specification then states:

These completely aqueous formulation approaches were then stopped and it was decided to use a vegetable oil to attempt to encapsulate the Abamectin and possibly protect it from the low pH of the water phase. An additional active, albendazole, a benzimidazole anthelmintic, was added to the formulation.

31 The specification states that the formulations described in examples 5 and 6, after ‘accelerated stability assays’ showed that the abamectin was degrading. It further stated that the physical stability of the formulations were also ‘poor with Albendazole flocculating out and with the oil phase showing evidence of curdling’.

32 The formulation described in example 7 sought to overcome flocculation by adding an ingredient to coat the albendazole and improve its solubility in water. Also, the emulsifying agent Teric 380 was added, and the ‘percentage of the oil phase was increased to 10% to increase the partition between the oil/water phase [and] possibly improve Abamectin stability’. The formulation was apparently successful in preventing flocculation but the specification stated that the ‘oil phase readily separated out’.

33 The specification states that the ‘oil/water phase required further stabilisation’. Examples 8 to 11 consisted of a series of water/oil/emulsifier blends to ‘optimise this aspect of the formulation’. Tween 80 was also trialled as a possible alternative to Teric 380. The conclusions from the examples were stated as follows:

As a result we concluded that

• Teric 380 was the better emulsifier, and

• the higher concentration of oil emulsion was the most stable option.

Accordingly, the proceeding examples trialled oil concentration from 35 to 60% w/v.

34 Examples 12 and 13 were trials of different thickeners and do not need to be set out in any detail here for the purposes of this proceeding.

35 Examples 14 to 16 consist of formulations with tweaked concentration and varying active ingredients that do not need to be set out in any detail at this point. However, the findings in relation to the formulations are invariably ‘(p)roduct stable under an accelerated stability programme’.

36 Finally, examples 17 and 18 use formulations with active ingredient benzimidazole in lactic acid. The stated findings in relation to these formulations are that ‘(t)hese soluble forms of benzimidazoles are likely to have advantage (more easily dermally absorbed) as pour-on formulations’.

37 At the end of the patent, the specific claims are set out, as follows:

The claims defining the invention are as follows:

1. A storage stable veterinary composition for oral administration comprising:

(i) at least one avermectin as a first active ingredient;

(ii) at least one organic liquid carrier which carries at least most of said first active ingredient to define an organic liquid phase;

(iii) levamisole as a second active ingredient;

(iv) at least one benzimidazole as a third ingredient; and

(vi) at least water which carries at least most of said second and third active ingredients to define an aqueous phase;

wherein said aqueous phase has a pH of less than 7 and includes an emulsifying agent(s);

wherein said avermectin is abamectin or ivermectin; and

wherein said aqueous and organic liquid phases exist in, or can be shaken or agitated into, the form of an emulsion with any particulate content if any, being at least substantially present in said aqueous phase.

2. A composition of claim 1, further including closantel as an additional third active ingredient.

3. A composition of claim 1 or claim 2, wherein the organic liquid carrier is selected from the group consisting of one or more oils including at least one mineral or vegetable oil; emollient esters; an alcohol having multiple carbons; diols and glycol esters.

4. A composition of any one of claims 1 to 3 as an emulsion.

5. A method of treating helminthiasis in a warm-blooded animal which method comprises orally administering to said animal an effective amount of the stable veterinary composition of any one of claims 1 to 4.

38 The combination drench sought to overcome the problem of chemical instability by separating the active ingredients into suitable chemical environments. Water was used as the carrier for those active ingredients which do not degrade in water and the actives that will degrade in water were carried separately. The two chemical environments are combined in a form that is physically stable in the sense that the two carriers can be mixed, whilst allowing the individual ingredients to retain their chemical activity for an appropriate amount of time.

39 The problem of how to carry all the active ingredients in a single formulation was solved by using water as the carrier for those ingredients (levamisole, benzimidazole and closantel) which do not degrade in water, whilst separating the ingredient (avermectin) which does degrade in water. Put simply, the composition of the invention utilises a ‘dual personality’ carrier system. It is the effective partitioning of these two environments that forms the basis of the invention described and claimed in the patent specification.

40 The result is a practically workable product which can be used as an oral drench delivering reliable dosage amounts of each ingredient to the animal being treated.

ALLEGED INFRINGEMENT OF THE PATENT

41 Nufarm alleges that Jurox has, some time after 16 January 2004, infringed each of the claims 1 to 5 of the patent by exploiting the invention described by those claims. Nufarm alleges in essence that Jurox has, without the license or authority of Nufarm, made, sold or otherwise disposed of a composition marketed under the name Q-Drench, which, according to Nufarm, infringes each of the five claims in the patent. Q-Drench is principally marketed as an oral drench for sheep.

42 In its defence, Jurox conceded, relevantly, the following:

1. Jurox has, since 16 January 2004, made, sold and offered for sale a composition known as Q-Drench.

2. Q-Drench is a stable storage veterinary composition for oral administration falling within the scope of claims 1, 2, 3 and 4 of the patent, subject to denials that:

• the aqueous and organic liquid phases of the Q-Drench product exist in, or can be shaken into, the form of an emulsion; and

• the Q-Drench product is an emulsion.

43 In a cross-claim, Jurox alleged the patent was invalid in any event.

44 However, it is noted that, on 10 December 2004, the Court ordered:

The question whether the respondent/cross-claimant has infringed [the Patent] be heard and determined separately from and prior to all other questions in the proceedings, including all questions of the validity of the Patent and the quantum of any pecuniary relief.

45 Accordingly, the only issue to be determined by the Court at this stage is whether Jurox has infringed all the claims of the patent by manufacturing and selling the Q-Drench product.

46 The primary issue in this case is therefore whether or not Q-Drench is an ‘emulsion’ or is capable of being ‘shaken or agitated into the form of an emulsion’ as required by the claims of the patent. A closely related issue is whether or not Q-Drench has an ‘organic liquid phase’ and an ‘aqueous phase’ as those phrases are defined by the claims.

47 The proceeding is brought by reference to s 13 of the Patents Act 1990 (Cth) (‘the Act’). This section identifies the body of exclusive rights afforded to a patentee, and that is the exclusive right to exploit the invention and to authorise another person to exploit it. The requirement for infringement must be found in the general law having regard to the statutory monopoly conferred by s 13 of the Act. Jurox will have infringed the patent if it is shown that it has ‘exploited’ in Australia a product (or method) which possesses each and every one of the essential features of the relevant claims.

Skilled addressee

48 The construction of the specification is to be approached by the Court through the eyes of a non-inventive worker in the field – the skilled addressee.

49 In Root Quality Pty Ltd v Root Control Technologies Pty Ltd (2000) 49 IPR 225 at 241-242 Finkelstein J stated:

Generally speaking the skilled addressee is the person who works in the art or science with which the invention is connected. In Plimpton v Malcolmson (1876) 3 ChD 531 Jessel MR said (at 556):

What is meant is that if [the invention] is a manufacture connected with a particular trade, the people in the trade shall know something about it; if it is a thing connected with a chemical invention, people conversant with chemistry shall know something about it.

In Catnic Lord Diplock said (at 242) that skilled addressees are "those likely to have a practical interest in the subject matter of [the] invention". A variety of people may have that interest. There are those who might wish to make or construct the invention, those who may wish to compound the invention and those who may wish to use the invention. The skilled addressee seems to me to be a relative expression which does not identify any specific person. Because the patent is directed to a person interested in making, constructing, compounding or using the invention (see for example s 27(3)(b) of the Patent Act 1993 (Canada); International Standard Electric Corporation v Ooms 157 F2d 73 (1946)), this hypothetical person, the patent lawyer’s "reasonable man", may be required to be skilled in more than one art. Such a person might be thought of as the composite being, mentioned by Buckley LJ in Tetra Molectric at 583. It may be preferable not to search for a composite addressee but a team whose combined skills are to be employed.

50 The relevant skilled addressee for the purposes of this proceeding is a person skilled in chemistry, and particularly physical chemistry.

Construction of the Patent

51 The question of infringement is prefaced by a proper understanding of what is described in the body of the specification and a proper construction of the claims: see Sartas No 1 Pty Ltd v Koukourou & Partners Pty Ltd (1994) 30 IPR 479 at 486 per Gummow J.

52 In determining the meaning to be given to the words of a patent claim the court must make a ‘common sense assessment of what the words used convey’ in the context of the knowledge prevailing in the relevant art at the priority date. In Populin v HB Nominees Pty Ltd (1982) 41 ALR 471 the Full Court stated at 476:

The complete specification must not be read in the abstract but in the light of common knowledge in the art before the priority date, bearing in mind that what is being construed is a public instrument which must, if it is to be valid, define a monopoly in such a way that it is not reasonably capable of being misunderstood (see generally Welch Perrin & Co Pty Ltd v Worrel [1960] HCA 91; (1961) 106 CLR 588 at 610). The essential features of the product or process for which it claims a monopoly are to be determined not as a matter of abstract uninformed construction but by a common sense assessment of what the words used convey in the context of then-existing published knowledge.

53 In Décor Corp Pty Ltd v Dart Industries Inc (1988) 13 IPR 385 at 400, Sheppard J distilled ten rules of construction from the authorities:

(1) The claims define the invention which is the subject of the patent. These must be construed according to their terms upon ordinary principles. Any purely verbal or grammatical question that can be answered according to ordinary rules for the construction of written documents is to be resolved accordingly.

(2) It is not legitimate to confine the scope of the claims by reference to limitations which may be found in the body of the specification but are not expressly or by proper inference reproduced in the claims themselves. To put it another way, it is not legitimate to narrow or expand the boundaries of monopoly as fixed by the words of a claim by adding to those words glosses drawn from other parts of the specification.

(3) Nevertheless, in approaching the task of construction, one must read the specification as a whole.

(4) In some cases the meaning of the words used in the claims may be qualified or defined by what is said in the body of the specification.

(5) If a claim be clear, it is not to be made obscure because obscurities can be found in particular sentences in other parts of the document. But if an expression is not clear or is ambiguous, it is permissible to resort to the body of the specification to define or clarify the meaning of words used in the claim.

(6) A patent specification should be given a purposive construction rather than a purely literal one.

(7) In construing the specification, the court is not construing a written instrument operating inter partes, but a public instrument which must define a monopoly in such a way that it is not reasonably capable of being misunderstood.

(8) The body, apart from the preamble, is there to instruct those skilled in the art concerned in the carrying out of the invention; provided it is comprehensive to, and does not mislead, a skilled reader, the language used is seldom of importance.

(9) Nevertheless, the claims, since they define the monopoly, will be scrutinised with as much care as is used in construing other documents defining a legal right.

(10) If it is impossible to ascertain what the invention is from a fair reading of the specification as a whole, it will be invalid. But the specification must be construed in the light of the common knowledge in the art before the priority date.

54 In Sartas No 1 30 IPR at 485-486, Gummow J set out the following propositions:

The construction of the patent plainly is a matter of primary importance in the litigation. In Glaverbel SA v British Coal Corp [1994] RPC 443 at 485-486, Mummery J set out a number of what his Lordship said were uncontroversial propositions as to construction. Some of these are certainly applicable here, as being in accordance with the development of the law in Australia. From what was said by his Lordship useful guidance, in particular, is to be derived from the following propositions. Some of them were applied in rulings on evidence in the course of the trial. They are:

(1) It is for the court, not for any witness, however expert, to decide the question of construction in accordance with the meaning of the language used. Evidence can be given by experts to enlighten the judge on the meaning which those skilled in the art would give to technical or scientific terms and phrases and on unusual or special meanings given by such persons to words which might otherwise bear their ordinary meaning.

(Cf Agfa-Gevaert Ltd v Collector of Customs (1994) 124 ALR 645.)

(2) The specification should be construed without reference to the prior documents relied on as a ground for invalidity with a view to avoiding the effect of the prior documents. A fortiori, documents subsequent to the complete specification are inadmissible in aid of its construction.

(3) ... it is not permissible to construe the claims by reference to the subjective thoughts, intentions, purposes and opinions of the patentee or his witnesses or by reference to his actions before or after the grant of the patent.

(4) In reading the specification as a whole the different functions of the claim and the rest of the specification should be observed. The claim, cast in precise language, marks out the legal limits of the monopoly granted by the patent: and "what is not claimed is disclaimed". The specification describes how to carry out the process claimed and the best method known to the patentee of doing that. Although the claims are construed in the context of the specification as a whole, it is not permissible to restrict, expand or amend the clear language of a claim by reference to a limitation or gloss in the language used in the earlier part of the specification, but not repeated in the claim itself. It is legitimate, however, to refer to the rest of the specification to explain the background to the claims, to ascertain the meaning of the technical terms and resolve ambiguities in the construction of the claims.

The passage which I have emphasised is better understood by reference to the remarks of Taylor J in Martin v Scribal Pty Ltd [1954] HCA 48; (1954) 92 CLR 17 at 97 (affd [1956] HCA 32; 95 CLR 213 (PC)):

Plain language must be given its plain meaning, and clear words in a claim must not be tortured into an unnatural meaning by importing passages from the body of the specification: see Lord Russell’s speech in Electrical and Musical Industries Ltd v Lissen Ltd (1939) 56 RPC at 41, line 34). The claims must also be construed without an eye on the alleged infringer’s acts. (So said Greene LJ in RCA Photophone Ltd v Gaumont British Picture Corp (1936) 53 RPC at 202, line 16). On the other hand, it is right to construe a claim with an eye benevolent to the inventor and with a view to making the invention work – this is an application of the old doctrine ut res magis valeat quam pereat – and is illustrated in Nobel’s Case (1894) 11 RPC at 524; and, where the language of a claim is obscure or doubtful, the doubt may sometimes be resolved by referring to words in the body of the document to explain it. This is known as the dictionary principle: see Lord Haldane’s speech in British Thomson-Houston Co Ltd v Corona Lamp Works Ltd (1921) 39 RPC at 67, line 44).

See also Melbourne v Terry Fluid Controls Pty Ltd (1994) AIPC 91-058 at 38,214; CCOM Pty Ltd v Jiejing Pty Ltd (1994) 122 ALR 417 at 424.

55 The High Court recently confirmed in Kimberly-Clark Australia Pty Ltd v Arico Trading International Pty Ltd [2001] HCA 8; (2001) 207 CLR 1 that the specification and claims must not be read in the abstract. Rather, the specification and claims must be construed in light of the common general knowledge and the art before the priority date. Chief Justice Gleeson, McHugh, Gummow, Hayne and Callinan JJ said at [24]:

...[the complete specification] is to be construed in the light of the common general knowledge and the art before...the priority date; the court is to place itself "in the position of some person acquainted with the surrounding circumstances as to the state of [the] art and manufacture at the time.

56 More recently, Bennett J made the following observations in Sachtler GMBH & Co KG v RE Miller Pty Ltd (2005) 221 ALR 373 at [42] (referred to by the Full Court in Synthetic Turf Development Pty Limited v Sports Technology International Pty Limited (2005) 67 IPR 475):

• When determining the nature and extent of the monopoly claimed, the specification must be read as a whole. As a whole it is made up of several parts and those parts have different functions. The claim, cast in precise language, marks out the legal limits of the monopoly granted by the patent. What is not claimed is disclaimed. The specification describes how to carry out the process claimed and the best method known to the patentee of doing that: Beltreco at [73].

• Although the claims are construed in the context of the specification as a whole, it is not legitimate to narrow or expand the boundaries of monopoly, as fixed by the words of a claim, by adding to those words glosses drawn from other parts of the specification. If a claim is clear and unambiguous, it is not to be varied, qualified or made obscure by statements found in other parts of the document: Beltreco at [74].

• Terms in the claim which are unclear may be defined or clarified by reference to the body of the specification: Welch Perrin at 610; Interlego at 479, both approved in Kimberly-Clark at [15].

• Reference may be made to the body of the specification to understand the context in which words have been used: Beltreco at [77] following Minnesota Mining & Manufacturing Co v Beiersdorf (Aust) Ltd [1980] HCA 9; (1980) 144 CLR 253 at 272.

• It is legitimate to refer to the rest of the specification to explain the background to the claims, to ascertain the meaning of technical terms and to resolve ambiguities in the construction of the claims. Where the language of the claim is obscure or doubtful the doubt is sometimes resolved by referring to words in the body of the document to explain it: Beltreco at [75].

• It is not necessary first to construe the claims without reference to the specification and then to determine whether or not ambiguity exists: Décor at 410; Beltreco at [76]; PhotoCure at [174].

• There is a fine line between, on the one hand, reading down the words of a patent claim to reflect how a person skilled in the art would understand it in a practical and commonsense way and, on the other hand, impermissibly limiting the clear words of a claim because a reader skilled in the art would be likely to apply those wide words only in a limited range of all the situations they describe: Stanway Oyster Cylinders Pty Ltd v Marks (1996) 66 FCR 577 at 585 per Drummond J.

• The construction of the claim determines infringement, on both textual and substantive bases: Catnic Components Limited v Hill & Smith Ltd [1982] RPC 183 at 242 at 242; PhotoCure at [158]. It is a question of whether the alleged infringement is covered by the language of the claim: Improver Corporation v Remington Consumer Products Ltd [1990] FSR 181 at 189-190 cited in Photocure at [158].

• A patent should be given a purposive construction: Catnic at 242-3. However, that does not involve extending or going beyond the definition of the technical matter for which the patentee seeks protection in the claims. The question is always what the person skilled in the art would have understood the patentee to be using the language of the claim to mean. For this purpose, the language chosen is usually of critical importance: Kirin-Amgen Inc v Hoeschst Marion Roussel Ltd [2004] UKHL 46; (2004) 64 IPR 444; [2005] 1 All ER 667 at  [34].

• Purposive construction, permitting consideration of whether the person skilled in the art would understand a variant that does not strictly comply with the particular descriptive word used in the claim may still fall within the monopoly, does not arise where the variant would in fact have a material effect upon the way the invention worked: Catnic at 243; Kirin-Amgen at [50].

57 It is clear that in construction of patents, one is not concerned with what the author meant to say. It is rather, what the notional addressee would have understood the author to mean by using those words: see Kirin-Amgen Inc v Hoechst Marion Roussel Ltd (2004) 64 IPR 444 per Lord Hoffman at [32]. His Lordship went on to consider at [34] what is meant by ‘purposive construction’, as follows:

"Purposive construction" does not mean that one is extending or going beyond the definition of the technical matter for which the patentee seeks protection in the claims. The question is always what the person skilled in the art would have understood the patentee to be using the language of the claim to mean. And for this purpose, the language he has chosen is usually of critical importance. The conventions of word meaning and syntax enable us to express our meanings with great accuracy and subtlety and the skilled man will ordinarily assume that the patentee has chosen his language accordingly. As a number of judges have pointed out, the specification is a unilateral documents in words of the patentee’s own choosing. Furthermore, the words will usually have been chosen upon skilled advice. The specification is not a document inter rusticos for which broad allowances must be made. On the other hand, it must be recognised that the patentee is trying to describe something which, at any rate in his opinion, is new; which has not existed before and of which there may be no generally accepted definition. There will be occasions upon which it will be obvious to the skilled man that the patentee must in some respect have departed from conventional use of language or included in his description of the invention some element which he did not mean to be essential. But one would not expect that to happen very often.

58 It is well settled that the plain and unambiguous meaning of a claim cannot be varied or qualified by reference to the body of the specification. In particular, it is not legitimate, in the absence of an express reference in the claim itself to import into a claim, features of the preferred embodiment. The preferred embodiment cannot be used to introduce into the definite words of a claim an additional definition or qualification of the patentee’s invention.

RELEVANT TECHNICAL CONCEPTS

59 The dispute between the parties stems from ambiguities which exist as a result of certain wording used in the patent. Fundamentally, those ambiguities reflect a difference of opinions within the relevant audience, namely the skilled addressee, as to the proper meaning of the words ‘emulsion’ and ‘phase’. I set out below a relatively brief summary of the competing views as to the correct definition of these words, along with some other chemical principles and concepts which are relevant to the current dispute and to the evidence which was given during the course of the trial.

What is a ‘phase’?

60 It may well be that, theoretically, there is no contention about the basic definition of a phase, namely, that it is ‘any part of a system which is uniform in chemical and physical properties and is separated from other homogenous parts of the system by boundary surfaces’. In practice however, there is debate amongst experts as to the proper classification of certain given examples. It seems to be accepted that the concept of ‘a phase’ is context-specific, and will depend upon the function of the product itself.

61 It was agreed by the experts at trial that examples of a one phase system included:

• Pure water. The water is uniform in chemical and physical properties and is separated from the glass containing it by a water-glass boundary.

• Sugar dissolved in water. Although the sugar solution has two components, sugar and water, the sugar exists as individual molecules uniformly dispersed throughout the water. The sugar solution is therefore uniform in chemical and physical properties and the sugar solution is, accordingly, one phase.

• Alcohol mixed with water. Like the sugar solution this example has two components, ethanol and water. Ethanol and water are said to be completely miscible; that is, the mixture consists of ethanol molecules and water molecules uniformly mixed. The ethanol-water mixture is therefore uniform in chemical and physical properties and is accordingly a one phase system.

62 It was also agreed that an example of a two phase system is olive oil shaken with water. This has two components, oil and water, but in this case the oil does not dissolve in the water as individual molecules but rather disperses as droplets of oil throughout the water. Each oil droplet is uniform in chemical and physical properties separated from the water by a boundary. The oil and water system is a two phase system consisting of an oil phase and a water phase.

63 Some experts consider that, to constitute a separate phase, there must be in essence a ‘threshold’ in terms of the number of molecules of the substance in question. This is well illustrated by the example of the surfactant Tween 80 in water. Tween 80, once it has reached the critical micelle concentration, or CMC, does not disperse in water as individual molecules but rather exists as many aggregates, each aggregate consisting of about 50-100 Tween 80 molecules and having a hydrophilic (water-loving) exterior and hydrophobic (water-hating) interior. One school of thought considers that the aggregates, or micelles, do not constitute a phase separate from that of the water because there are insufficient numbers of the Tween 80 molecules in each micelle to give that micelle uniform chemical and physical properties separate from the water around it. That is, the interior part of the micelle is not big enough to possess uniformity. Followers of this theory believe that there is a ‘critical mass’ of molecules at which point a separate phase is formed. The opposing school believes however that should be no such threshold; that the 50-100 Tween 80 molecules in a micelle satisfies the definition of a phase.

Emulsions

64 The differing of opinion in relation to the definition of a phase has implications for the interpretation of the term ‘emulsion’ as it is used in the patent claims.

65 Put simply, an emulsion is a dispersion of one liquid in another, or a system in which there is a separation of one liquid phase from another. An obvious contention which arises then is the discrepancy in the meaning of phase.

66 The definition of ‘emulsion’ varies slightly between dictionaries and chemistry texts:

• The Macquarie Dictionary (2^nd ed):

2. any colloidal suspension of a liquid in another liquid. 3. Pharm. A liquid preparation consisting of minute particles of an oily, fatty, resinous, or other substance held in suspension in an immiscible, usu. aqueous fluid by means of a gum or other viscous matter.

• Penguin Dictionary of Chemistry (5^th ed):

An emulsion is a disperse system in which both phases are liquids; generally one of the liquids is water or an aqueous solution, and the other an oil or other water-immiscible liquid.

• Hawley’s Condensed Chemical Dictionary (11^th ed, John Wiley & Sons, 2001):

A stable mixture of two or more immiscible liquids held in suspension by small percentages of substances called emulsifiers.

• The Colloidal Domain (‘Evans’, VCH, 1994):

Emulsions are mixtures of two immiscible liquids, such as oil and water, stabilised by an emulsifier.

• Foundations of Colloid Science (2nd ed, Oxford University Press), refers to an emulsion as a colloidal dispersion of one liquid dispersed (the dispersed phase) in another (the dispersion medium) with a lower limit of the dispersed phase being around 1nm.

67 Some scientists consider that thermodynamically instability is a defining feature of an emulsion; some definitions from texts reflecting this position are set out below.

• Kirk-Othmer Concise Encyclopaedia of Chemical Techonology (Wiley-Interscience publication):

An emulsion is a mixture of two or more immiscible liquids, one being present in the other in the form of droplets...Emulsions are inherently unstable systems and the risk of deteriorating during storage is greater than with a nonemulsified product.

• The Theory and Practice of Industrial Pharmacy (3^rd ed, Lea & Febiger, 1986):

A precise definition of the term emulsion depends on the observer’s point of view. The physical chemist defines an emulsion as a thermodynamically unstable mixture of two essentially immiscible liquids. For the product development technologist, it is more useful to regard an emulsion as an intimate mixture of two immiscible liquids that exhibits an acceptable shelf life near room temperature. Other definitions exist, but the two given here suffice for the purpose of this chapter.

Micellar systems, microemulsions, macroemulsions and their classification

68 Another relevant and contentious issue is the meaning of the terms ‘microemulsion’ and ‘macroemulsion’. Broadly speaking, the extent of agreement between experts is that a microemulsion contains smaller droplets of the organic phase than in a macroemulsion. After that, the thinking diverges, with points of difference including the following:

• Whether ‘macroemulsion’ is synonymous with ‘emulsion’, with microemulsions consisting of one phase and therefore being in a separate class altogether, or whether microemulsions and macroemulsions are simply subclasses of emulsions.

• Whether microemulsions are thermodynamically stable, and are distinguishable from macroemulsions on that basis.

69 For the purposes of this proceeding, micelles maybe considered to be relatively small aggregates of molecules with a hydrophilic exterior and hydrophobic interior. Tween 80, when added to water in levels above its CMC, forms micelles in the water. When another organic substance is added to the Tween 80/water mix, that organic material may enter the hydrophobic centre of the micelle, forming what is known as a ‘swollen micelle’.

70 Debate exists as to whether a micellar system is properly to be regarded as an emulsion. Some argue that the presence of an organic region within the micelle is enough to render it an emulsion by definition. Others consider that, in practice, the mere lack of numbers of molecules within a micelle mean that it does not have not have the properties of a separate phase and cannot therefore be an emulsion of any type. Still others consider that a one phase emulsion is possible, and see a microemulsion as a one phase system.

71 Those who consider that a micellar system is an emulsion view the classification of emulsions as a continuum, ranging from micellar solutions (having the smallest droplets/regions of organic material), through swollen micelles, microemulsions, and macroemulsions (having the largest droplets of organic material). Microemulsions with very small organic regions, or droplets, appear transparent to the human eye. Accordingly, some see clear emulsions, micellar systems, and microemulsions as one and the same.

72 Those that do not consider micellar systems to be emulsions may refer to the increased thermodynamic stability of emulsions as the size of the organic droplets reduces. The less thermodynamically stable a mixture is, the more likely it is that the organic regions will coalesce and separate out into layers, with each layer being a phase. A surfactant reduces the size of the droplets, and increases the thermodynamic stability of the mixture.

73 Centrifugation is a method by which an emulsion may be forced into its two component phases. There is, accordingly, a school of thought that a mixture which cannot, by centrifugation, be separated into two layers does not consist of two phases and is not an emulsion. This school does not consider that micellization results in the formation of droplets or, therefore, that micellar systems are within definitions of an emulsion.

74 The parties to this proceeding agree that Q-Drench is a (swollen) micellar system. The patent covers an invention which contains a liquid organic phase and which is an emulsion. Accordingly, given the variation of opinions about the proper classification of micelles, the parties dispute whether Q-Drench falls within the terms of the claims.

ANALYSIS

75 As noted earlier, the primary contention of Nufarm is that Jurox’s Q-Drench product infringes claim 1 of the patent in suit. As Nufarm acknowledges, claims 2 to 5 are dependent claims.

76 Jurox, for its part, rejects the contention that its product infringes claim 1, denying that Q-Drench possesses four of the integers of claim 1. Specifically, Jurox denies that Q-Drench:

• has an organic liquid that acts as a liquid carrier;

• has an organic liquid phase;

• has any phase which exists in, or can be shaken or agitated into, the form of an emulsion; or

• is an emulsion.

77 The parties essentially agree that the instant dispute can be further reduced to two related questions: (1) does Q-Drench have an ‘organic phase’; and (2) is it an ‘emulsion’ within the meaning of those terms as used and understood in the patent in suit. To state the case affirmatively, Jurox’s basic claim is that ‘the Q-Drench product is not an emulsion, but a micellar solution of a single aqueous phase.’

78 It is common ground between the parties that the term ‘emulsion’ can be used to describe a variety of mixtures depending on the circumstances, including relevantly the droplet size of the dispersed liquid. From there, however, the parties’ positions diverge.

79 Nufarm submits that in the context of the patent:

...the term "emulsion" properly includes macroemulsions, coarse emulsions [both having large droplets], microemulsions, swollen micellar systems and micellar solutions. The term "microemulsion" refers to an emulsion where the dispersed liquid is in the form of small droplets or aggregates. These dispersed droplets can be in the order of a few nanometres in size. Microemulsions are also on occasion referred to as "micellar solutions". These terms are synonyms, as is the term "swollen micelle". Therefore, even accepting Jurox’s characterisation of Q-Drench as a "micellar system" or "micellar solution", it is still in the form of an emulsion as claimed.

80 Jurox responds that:

...[e]ven if other forms of dispersions which are discussed in the evidence – "micellar solutions" and "microemulsions" – are in other contexts properly regarded as emulsions – a controversial point – they are not within the claims of the Patent....

Thus, according to Jurox, the term ‘emulsion’ as used in claim 1 should be construed to cover only macroemulsions (ie large-droplet size) and to exclude micellar solutions (ie small-droplet size) such as Q-Drench given:

• limiting language in the patent specifications, in particular the examples of formulas leading up to the patented Nufarm formula; and

• prior art, specifically a patent known as the ‘Merck patent’, already dealing with microemulsions.

81 I have earlier set out the basic principles of patent construction, but it is useful at this point to reiterate and emphasise certain points regarding the construction of a patent’s claim language in light of the language in the specifications. It is legitimate to refer to the specification as a whole to resolve ambiguities in the construction of claims and to resort to the body of the specification to define or clarify the meaning of words used in the claim. Moreover, the fundamental rule is that the claims and specifications must be read together.

82 In light of my discussion above as to the relevant technical concepts, I have come to the view that the word ‘emulsion’ and the application of the expression ‘phrase’ used in the claims are capable of more than one meaning and lack clarity. It is permissible to look to the body of the specification to aid in the construction of the claim.

83 With these principles in mind, I turn directly to the examples in the specifications to assist in understanding the meaning of the term emulsion in claim 1. As Nufarm accepts, the composition of the Q-Drench product is very similar to the formulations of examples 1 to 4 of the specification. The similarities can be seen from the following table, which compares the composition of Q-Drench with that of the example formulae found in the specifications of the patent in suit (as well as the Merck oral drench):

		Examples 1 to 4 in the patent	Examples 5 to 7 in the patent	Examples 12 to 16 in the patent	Q-Drench	Merck oral drench
Item	Ingredient	% w/v	% w/v	% w/v	% w/v	% w/v
1	Abamectin	0.2	0.1	0.1	0.105	-
2	Ivermectin	-	-	-	-	0.08
3	Tween 80	8.0	None	None	15.0	8.0
4	Benzyl alcohol	3.0	3.0	3.0	3.0	3.0
5	Propylene glycol	20.0	3.0	3.0	20.0	20.0
6	Soya Bean Oil	None	3.0-10.0	10.0-40.0	None	None
7	Tersperse 4896	None	0.0-1.0	1.0-2.0	None	None
8	Tersperse 2500	None	0.0-2.0	2.0	None	None
9	Teroc 380	None	0.0-5.0	5.0	None	None
10	Teric 21S	None	10.0	-	None	None
11	Teric 216	None	10.0	-	None	None
12	Na2HPO4	1.03	1.05	None	0.1	0.1
13	2Na HPO4	-	-	-	0.9	0.9
14	Citric acid	0.29	1.21	-	-	-
15	Levamisole HCl	8.0	3.75-4.0	3.75-4.0	4.0	-
16	Sodium selenate	0.24	0.12	0.0-0.12	-	-
17	Aerosil 200	-	-	-	1.8	-
18	Xanthan gum	-	0.2-0.32	0.0-0.3	-	-
19	Cellulose gum CMC	0.5	-	-	-	-
20	Carbopol 934	0.5	-	-	-	-
21	Water to volume	qs	qs	qs	qs	qs
22	Closantel	-	-	-	3.75	-
23	Albendazole	-	1.9-2.5	1.9-2.5	2.5	-
24	Oxfendazole				0-2.6

84 As the boldfaced items indicate, there is a key group of eight ingredients as to which Q-Drench, the Merck drench, and examples 1 to 4 of the Nufarm specification all have similar concentrations and on which basis they can be sharply contrasted to examples 5 to 7 and 12 to 16 of the patent. In particular, the following differences between examples 1 to 4 are potent:

• In each of examples 1 through 4, the abamectin, Tween 80 and benzyl alcohol content are exactly the same. In example 5 however, the ratio of oil to surfactant increases.

• Tween 80, the surfactant used in each of examples 1 through 4, is replaced by Teric.

85 Each side therefore relies on examples 1 to 4 to support its preferred construction of the claims. On the one hand, Nufarm submits that examples 1 to 4 are illustrations of formulae that are claimed in the patent, so that Q-Drench, being like those examples, comes within the claim language. On the other hand, Jurox submits that examples 1 to 4 are illustrations of formulae that are not claimed in the patent, so that Q-Drench, being like those examples, is excluded from the monopoly claimed by Nufarm.

86 The question before the Court on this point, then, is whether a skilled addressee would, having regard to the patent as a whole, understand an emulsion of the type claimed by Nufarm to include solutions such as those found in examples 1 to 4 (and thus also Q-Drench) or exclude them. Resolution of this dispute requires a close reading of examples 1 to 4 in context.

87 The context of examples 1 to 4 is this: they are the first four of a series of 18 examples in the specifications set out to describe the process by which Nufarm developed and ultimately arrived at the invention claimed. Indeed, Nufarm characterises the examples as follows: ‘The sequence of the examples demonstrates a logical development of a better, more chemically stable formulation...’. Further, Nufarm agrees that the formulations in examples 1 to 4 describe micellar solutions/microemulsions, although it disputes that the failure to find a successful, stable micellar solution means that microemulsions/micellar solutions are thereby disclaimed:

Although the inventors "stopped" work on the micellar solutions/microemulsions shown in (e)xamples 1 to 4[,] it cannot be concluded that the use of micelles or microemulsions to partition the incompatible ingredients was "abandoned".

88 Nufarm argued that:

• It does not follow that by using a small amount of vegetable oil the inventors were looking to necessarily move to a macroemulsion system.

• It would not necessarily have been apparent that a macroemulsion would result from the use of the ingredients of examples 5 and 6.

• It was only after the formulations were made and tested that it was determined that they lacked the physical stability of a microemulsion or a micellar solution.

• It is reasonable to infer that in resolving to introduce vegetable oil in examples 5 and 6 the inventors did not know whether this would adequately protect the abamectin or whether the addition of vegetable oil would result in a micellar solution, microemulsion or macroemulsion.

• It could not be known whether the addition of a small amount of vegetable oil would simply result in ‘a more highly swollen micellar system’.

89 It is important to recall that the Court must itself consider the language of the patent as a whole. Expert witnesses gave evidence as to their views on the significance of examples 1 to 4, and whether they were ‘abandoned’ or not, but it is for the Court, enlightened by the evidence of experts, to determine itself the construction to be placed upon the patent. I am to focus on the patent itself, not on the evidence of the expert witnesses, who opined on the theoretical or possible thoughts, intentions, purposes and opinions of the patentee. Once the Court has reached the conclusion (as it has) that there is lack of clarity in the claims, I can resort to the body of the specification to provide the clarity as a matter of construction.

90 I have already set out the examples in the body of the specification. Importantly, though, after describing the failed attempt in example 1, the patent states:

This resultant formulation was physically stable but considered too thin. To correct this the following (e)xamples 2 - 4 were thickened with Carbopol or gums.

91 Then, after describing the failed attempts in examples 2 to 4, the patent recites:

The low pH of these formulations 2, 3 and 4 (pH<4) was identified as unsuitable for the long-term stability of Abamectin. These completely aqueous formulation approaches were then stopped and it was decided to use a vegetable oil to attempt to encapsulate the Abamectin and possibly protect it from the low pH of the water phase. An additional active, albendazole, a benzimidazole anthelmintic, was added to the formulation.
(Emphasis added)

92 The work on micellar formulas like examples 1 to 4 stopped (as Nufarm accepts). The use of the phrase ‘completely aqueous formulation’ to describe those formulae, when read in light of the language of claim 1, indicates that the attempt to claim a micellar solution/microemulsion was abandoned, or disclaimed in the patent. It will be recalled that claim 1 provides that both an organic phase and an aqueous phase are required for the purpose of the invention and that the formula claimed is stable for an extended period of time. It thus follows that the formulas of the type found in examples 1 to 4 are to be considered outside the claims as they are described as: (a) completely aqueous (ie no organic phase); and (b) unsuitable for long–term stability. It then further follows that Q-Drench, a micellar solution which Nufarm concedes is ‘very similar to’ to examples 1 to 4, also falls outside the scope of claim 1.

93 I note that Mr Parris, who has a Master of Science degree in physical chemistry, and is now a consultant in the field of physical chemistry, giving evidence on behalf of Nufarm, deposed:

The (e)xamples are clearly not all literal examples of the invention as claimed as a number of them do not include one or more of the components required by the claims.

94 Professor Tucker, Dean of the School of Pharmacy at the University of Otago in New Zealand, gave evidence on behalf of Jurox that, apart from the drugs and buffering agents, examples 1 to 4 contain Tween 80 (8%), benzyl alcohol (3%), propylene glycol (20%), made up to 100% with water, and that this is very similar to Q-Drench. The only difference between them is that in Q-Drench the percentage of Tween 80 is higher, at 15%. He deposed that, since Tween 80 does not in his opinion constitute an organic liquid phase, a higher concentration of Tween 80 (ie 15% rather than 8%) will not create an organic liquid phase. Professor Tucker considered that, given the phrase ‘completely aqueous formulation’ was being correctly used to describe examples 1 to 4 in the patent, Nufarm did not consider that the benzyl alcohol formed an organic liquid phase and therefore went on to use vegetable oils to provide an organic phase.

95 Mr Parris agreed with Professor Tucker that examples 1 to 4 of the specification are similar to Q-Drench, but deposed that the difference in the amount of surfactant did not alter his characterisation of the Q-Drench as an emulsion. He gave evidence that:

...(T)he (e)xamples are all directed to exemplifying the major concept underlying the invention, namely a carrier system by which, two (or more) incompatible active ingredients can be carried in a single composition where one of these actives (levamisole) is in an acidic aqueous environment and the other active (abamectin) is chemically unstable in that acidic aqueous environment. The answer provided by the specification is to use a carrier system whereby the levamisole is in the required acidic aqueous environment but the abamectin is isolated or partitioned from that acidic aqueous environment by placing it in an organic liquid environment, such that the abamectin has limited exposure to the acidic aqueous environment, but which enables the mixture to be substantically homogenous to provide constant dosing.

96 Professor Grieser, a professor of chemistry at the University of Melbourne and giving expert evidence on behalf of Nufarm, agreed during cross-examination that the language of the claim ‘quintessentially’ describes a macroemulsion.

97 In any event, I must construe the patent myself having been assisted by the expert evidence, but not dictated by it. As a starting point, I do not consider that all the examples should be seen as illustrations of the patent as claimed. The specification, to my mind, gives the examples not to show what is covered by the patent, but to show how the final Nufarm formula was arrived at and to illustrate the inventive step or steps undertaken. From the language used in the specification, it is clear that the addition of a vegetable oil, in an attempt to encapsulate the abamectin, represented a departure from examples 1 to 4 towards a mixture with larger organic regions. I am happy to accept that examples 1 to 4 may not, in fact, be ‘completely aqueous formulations’. However, the phrase ‘completely aqueous formulation’ is of importance when construing the claims; the skilled addressee (the chemist) would have understood there to be a fundamental transition in the nature of the formulation after example 4. Regardless of whether examples 1 to 4 are properly classified as emulsions (of whatever variety) or not, the claims, when construed in light of the specification, do not, in my view, cover examples 1 to 4.

98 Nowhere is there a specific definition of ‘emulsion’. The patentee could have confined the patent specifically to macroemulsions, but did not specifically do so in the claims or specification. However, the patent could be properly limited so as not to include examples 1 to 4, for instance, or micelles. Micelles are different from macroemulsions, so there is some basis for the distinction. The real problem seems to be in determining whether a particular product fits within the scope of micelle or macroemulsion, or somewhere in between. It remains the case, however, that the language of the patent claims, with its reference to ‘organic liquid phase’ and ‘emulsion’ does not mirror or evoke the language used in examples 1 to 4. Quite the opposite is true.

99 If the various types of aqueous/organic liquid mixtures which have been referred to in this proceeding are considered as sitting on a spectrum from micelles on the one hand through to macroemulsions on the other hand, it is, to my mind, clear that the patent covers the formulations sitting towards the ‘macro’ end of the scale. Expert evidence was given for Nufarm that the patent, properly construed, covers microemulsions to some extent. I am happy to accept this as a possibility. This does not mean however that all microemulsions are covered. The evidence showed that there is a range of emulsions according to the size of their organic droplets. Accordingly, a patent may cover a subset of these emulsion sizes. It is quite open for me in light of the specification to conclude that the patent covers some microemulsions and not others, namely that the patent ‘kicks in’ somewhere after examples 1 to 4. Thus, even accepting that all examples in the specification are microemulsions, it does not necessarily follow that all microemulsions are covered by the patent. So, even accepting that a micellar solution such as Q-Drench is a microemulsion, it still does not, on my reading, fall within the scope of the patent. I need not come to a decision about where on the ‘emulsion spectrum’ the protection afforded by the patent comes to an end. I have concluded that examples 1 to 4 are not within the claims, and that the Q-Drench product is within these examples.

100 For the foregoing reasons, I conclude that Jurox’s Q-Drench product is not within claim 1 of the patent in suit. It follows that Q-Drench, not possessing all of the essential elements of claim 1 (and thus also the dependent claims), does not infringe.

OTHER EVIDENCE AND SUBMISSIONS

101 The parties relied on voluminous and diverse expert evidence in order to support their respective arguments about the proper classification of the Q-Drench formulation. Some of this evidence was essentially theoretical in nature in that it reflected the experts’ opinions as to the expected properties of the drench given details of the formulation. Other evidence was more empirical, and assessed the attributes of Q-Drench in light of its actual behaviour during testing.

102 Ultimately, my decision in this proceeding does not turn on any one piece of the expert evidence presented or any one theoretical argument relating to the chemical classification of Q-Drench. Nevertheless, I address below some of the key contentions between the parties in this respect. Some of the evidence given was relevant to two or more heads of argument; I have, however, endeavoured to deal with each aspect of the evidence once only.

103 In view of my approach to this proceeding as evidenced above, I need not come to any final view as to the credit of the witnesses called by either side. An attack was mounted upon certain expert witnesses, particularly Professor Tucker (called by Jurox) and Dr Cook (called by Nufarm). Despite these attacks, in my view each witness was attempting to assist the Court and provide their honest view. For my analysis, nothing turns upon the points of substance made in the parties’ submissions as to the discrepancy in the evidence of Professor Tucker or Dr Cook. Nevertheless, I will make brief mention of this matter later.

Does Q-Drench have one or two phases?

104 Professor Tucker gave evidence on behalf of Jurox that the Tween 80 micelles in water have a short half life of milliseconds to seconds, so that aggregates are continually forming and breaking up. He deposed that this is a one phase system.

105 Professor Tucker went on to depose that the definition of a phase implies that a phase contains a large number of molecules of its constituent components in order to fulfil the requirement of uniform chemical and physical properties and a boundary surface. Where there are only a few molecules of a particular chemical substance in close proximity (ie hundreds of molecules in a micelle compared with trillions in an oil droplet), Professor Tucker opined that this would not constitute a phase, as there would not be a sufficient aggregation of molecules to provide a region uniform in chemical and physical properties separated from other homogenous parts of the system by boundary surface. Given the relatively small number of organic molecules in the micelles containing the abamectin in Q-Drench, Professor Tucker considered therefore that Q-Drench is a one phase system.

106 Mr Parris disagreed with this position. He deposed that ‘in a solution there is no agglomeration of molecules of one liquid within the other’. In response, Professor Tucker gave example of true solutions where there exist agglomerations of solute molecules, such as benzoic acid in solution which, in some solvents, exists in the form of dimers. Mr Parris, in reply, said that he did not consider the formation of a dimer to be a mass of molecules. He went on to depose that, in his view, a system of micelles of Tween 80 in water is not a true solution but an emulsion, given that, in his opinion, micelles are not homogenous at a molecular level and do not exist as a uniformly dispersed mixture with water at a molecular level.

107 Nufarm argued that if Q-Drench were seen as being comprised of two liquid carriers, one carrying the organic abamectin and the other carrying the aqueous active ingredients, it could be concluded that two phases were present in the drench. It claimed that ‘the two liquid carriers referred to in the claims define the relevant liquid phases’ and that ‘claim 1 provides its own definition of what a "phase" is’. I do not accept this. As Nufarm itself points out, the term ‘carrier’ is not a term of art and does not bear a technical meaning. It is, in the claims, therefore being used descriptively and is in effect usurped by the use of the word ‘phase’ later in the claim. Even accepting that the abamectin is being ‘carried’ by an agglomeration of organic molecules or molecules containing organic portions, I do not consider that this necessarily means that those agglomerations are, in the context of the patent claims, separate phases from the continuous aqueous phase. An organic portion does not constitute a phase necessarily.

108 I appreciate that, as Nufarm contended, there may be no difference conceptually between the partitioning of the organic actives from the aqueous actives in examples 1 to 4, and the partitioning as defined in the claims. But that does not mean that all mixtures containing an organic molecule geographically isolated, or protected, from an aqueous solution will constitute two phases. As I have set out above, this is clear from the wording used in examples 1 to 4 of the patent.

109 Nufarm made much in its submissions of the precise composition of Q-Drench micelles (by percentage and molecule numbers), and the theorised location of the components within each micelle, with the experts disagreeing. Neutron scattering and nuclear magnetic resonance (‘NMR’) experiment data was tendered to this end. In particular, there was debate as to whether Q-Drench consisted of an emulsion, the organic liquid phase of which consisted of benzyl alcohol containing abamectin stabilised by Tween 80 as an emulsifying agent. Jurox argued that the nuclear magnetic resonance results definitively dismissed such a notion.

110 Dr Cook, for Nufarm, gave evidence that:

My conclusion that the Q-Drench is in the form of an emulsion is not dependant on either the PCS analysis or the cryo-SEM experiment referred to in my first affidavit. The evidence from the other experiments and analyses referred to in my first affidavit and in this affidavit are conclusive that the Q-Drench is in the form of an emulsion in which abamectin is dissolved in fine droplets of benzyl alcohol stablised by Tween 80 to form a dispersed phase in the continuous phase of water and propylene glycol.

111 In cross-examination, Dr Cook admitted that he had overstated the work previously undertaken, and that such work did not in fact even suggest that there were droplets of benzyl alcohol containing abamectin, stabilised by Tween 80. Jurox contended that Dr Cook was selective in his presentation of the NMR data concerned with the distribution of benzyl alcohol in the micelles, pointing to Dr Cook’s acceptance that he had ‘looked at only half of the story’ when dealing with the relative solubility of abamectin in benzyl alcohol compared with Tween 80. Dr Cook’s evidence must be read in light of these concessions, although on my analysis nothing turns upon this matter.

112 Evidence was also given about the gradient of polarity from the inside to the outside of the micelle, and about the likely location of the abamectin and benzyl alcohol along that gradient, and the relative solubility of abamectin in benzyl alcohol and Tween 80. Nufarm submitted that ‘(t)he benzyl alcohol is an organic liquid carrier that carries at least most of the abamectin as required by claim 1. Q-Drench has an organic liquid phase as required by integers 3 and 4 of claim 1’.

113 I reach no conclusion about this tranche of evidence relating to the structure of each micelle on the basis that, as I have already stated, I do not consider it necessary to determine what are essentially theoretical arguments and which do not require determination in order to resolve the central dispute.

114 One of the methods used to test whether Q-Drench consisted of one or two phases (and, similarly, the thermodynamic stability) was centrifugation. Jurox gave evidence that some definitions of emulsions require thermodynamic stability, although was happy to concede that the point is debatable.

115 Mr Parris and Professor Grieser both accepted that there was no experimental evidence of mechanical separation, despite attempts by Nufarm to do so. Evidence was given that the equipment used in the attempt to separate Q-Drench was ‘state of the art’. Mr Parris considered that the failure of centrifugation to separate Q-Drench into visible layers was merely reflective of high levels of surfactant in what he considered to be an emulsion. He also stated that he did not consider that an emulsion was necessarily thermodynamically unstable or that centrifugation was a reliable test for detecting the presence of an emulsion. He stated that whilst centrifugation may break many emulsions, it will not break all of them, including microemulsions.

116 Professor Tucker described a system comprising of Tween 80 and water as thermodynamically stable and that ultra-high speed centrifuging would usually not bring about coalescence of the product into separate layers of Tween 80 and water. He pointed out that even ‘heroic’ centrifuging of Q-Drench (700,000 g-force for 24 hours) failed to cause separation into a water phase and an organic liquid phase, and that the fact that this extreme ultracentrifugation did not separate the Q-Drench into discrete layers was strong evidence that Q-Drench is a thermodynamically stable one phase system. I found this approach to be compelling, moving away from the theoretical to the practical and pragmatic.

117 However, it was contended by Nufarm that micelles could theoretically be separated from the water surrounding them by a process called ultra-filtration which, in their submission, proved that a micellar solution comprised two phases. Evidence was given that, even if water could so be isolated from the micelles, the micelles would be destroyed in the process.

118 I need go no further into investigating this matter having regard to the approach I have taken to the central issue.

Micellar systems, emulsions and the classification of Q-Drench

Definitions of emulsion

119 One of the questions giving a relatively broad range of answers was the definition of an emulsion, as indicated previously by reference to various texts. It was accepted by all experts that Q-Drench is a micellar solution, but it was a point of contention between the parties as to whether, as a micellar solution, it is an emulsion as claimed in the patent. To that end, each of Nufarm’s witnesses gave evidence to the effect that an emulsion is a broad term, and is not confined to macroemulsions, as set out below.

120 Professor Grieser defined an emulsion as, ‘...a dispersion of one liquid in another. In other words, it is simply a system in which there is a separation of one liquid phase from another.’

121 Dr Lichti, a consultant with expertise is the fields of agricultural and medical formulation technology, defined an emulsion as, ‘...a dispersion of one liquid in another. A working formulator would define an emulsion in the following way: An emulsion is formed when two liquids are mixed together to produce a dispersed (internal) phase and a continuous (external) phase.’

122 Mr Parris defined an emulsion as, ‘... a stable mixture of two or more immiscible liquids.’ Dr Cook, an analytical chemist, defined an emulsion as, ‘[a] mixture of two or more immiscible liquids one being present in the other as fine liquid particles.’

123 Jurox’s evidence of the meaning of emulsion, on the other hand, generally included a reference to thermodynamic instability. For example, Professor White, professor of physical and theoretical chemistry at the ANU in Canberra, defined an emulsion as ‘...a thermodynamically unstable two phase system in which the oil phase remains in the form of droplets suspended in the aqueous phase.’

124 Nufarm gave evidence that texts dealing with emulsion technology generally use terms other than ‘emulsion’ in order to differentiate between different types or classes of emulsions. Professor Grieser considered that macroemulsions and microemulsions were each properly referred to as emulsions. He considered ‘emulsion’ to be a generic name which described a broad class of dispersions constituted by one fluid in another and that it would be ‘false’ to restrict the word emulsion to mean macroemulsion.

125 Mr Parris disagreed with Professors White and Tucker’s view that a micelle containing additional oil is not an emulsion. Mr Parris deposed that ‘there is no relevant scientific difference between systems containing "swollen micelles", microemulsions and macroemulsions. Each are to be properly regarded an emulsions [sic].’ In Mr Parris’ view, there is a ‘continuum from the empty micelle through swollen micelles/microemulsions to macro or coarse emulsions’. As soon as there is a single molecule of an oil inside a micelle, he considered, the difference between that and a large droplet of oil stabilized by a layer of surfactant is simply a matter of size, the amount of oil inside the protective surfactant aggregate, and whether that droplet provides a sufficiently protective microenvironment for the avermectin. Mr Parris accepted however that there is a variation of views in the scientific community about whether a microemulsion is properly to be regarded as an emulsion. In cross-examination, Mr Parris conceded that ‘most people in the industry would regard a microemulsion as a single phase system’, and stated further, that ‘micellar solutions and microemulsions are often described as single phase systems’.

126 Dr Lichti gave evidence that both microemulsions and macroemulsions are subsets of the general class or term ‘emulsion’, and conceded that the issue of whether instability is a defining feature of emulsions is ‘a really difficult question’. He provided a number of examples demonstrating that some academics refer to micellar solutions as two phase systems.

127 Nufarm submitted that Professor Tucker had deposed in his affidavit evidence that microemulsions are thermodynamically stable one phase systems, and that he had resiled from this view in cross-examination. Professor Tucker, however, did not depose to such a view; his evidence was that thermodynamically stable microemulsions are, in his view, one phase systems. As he explained during cross examination, he does not say in his affidavit that all microemulsions are thermodynamically stable.

128 Professor Tucker later went on to explain that, in his view, notwithstanding the notion that micellar systems, microemulsions and coarse emulsions may be considered to be a part of a spectrum, they may be either one or two phase systems depending on the composition, that is, the volume of organic material in the micelle or droplet. In the case of a dynamic micelle, Professor Tucker believed that it was a one phase system. I do not consider that Professor Tucker’s evidence on this matter was in any way compromised by the cross-examination; I accept his view of the different characteristics of systems within the ‘emulsion spectrum’, ranging from a micellar, one phase system to a coarse, two phase emulsion. In Professor Tucker’s words where ‘one phase’ ends and ‘two phase’ starts ‘becomes difficult to determine’.

129 It is also appropriate at this point to mention that there was a side dispute about the meaning of the term ‘particle’ in the specification which does not seem to underpin either party’s arguments but which, in Nufarm’s submission, undermined Professor Tucker’s credit. Professor Tucker gave evidence that ‘particle’, in the context of the patent, could apply to both solids and liquids. When Nufarm contended that this would render the patent nonsensical, Professor Tucker relised from this view in cross-examination. Whilst I accept the contention of Nufarm, and that in my view on this point Professor Tucker was incorrect in his interpretation of the concept of ‘particle’ in the patent, as I have said I do not consider that he was attempting to do other than honestly express his view. Further, I do not consider that this error on the part of Professor Tucker otherwise reflects upon the acceptance of his other evidence.

Are micellar systems emulsions?

130 Nufarm gave evidence that the term ‘swollen micelles’ is commonly treated as a synonym for microemulsions, citing various texts. Dr Lichti and Mr Parris also referred to swollen micelles and microemulsions as synonyms. Professor Grieser gave evidence that micellar solutions are a class of emulsions.

131 Jurox however, referred to The Theory and Practice of Industrial Pharmacy (3rd ed, Lea & Febiger, 1986) which states:

When two immiscible liquids are mechanically agitated, both phases initially tend to form droplets. When the agitation is stopped, the droplets quickly coalesce, and the two liquids separate. The lifetime of the droplets is materially increased if an emulsifier is added to the two immiscible liquids. Usually, only one phase persists in droplet form for a prolonged period of time. This phase is called the internal (disperse or discontinuous) phase, and it is surrounded by an external (continuous) phase...

An emulsifier functions and is operationally defined as a stabilizer of the droplet form (globules) of the internal phase...

...

The particle size of the disperse phase determines the appearance of an emulsion. The radius of the emulsified droplets is an opaque, usually white, emulsion ranges from 0.25 to 10 microns. It is fairly well established that dispersed particles having a diameter of less than 1/4 the wave length of visible light, i.e., less than approximately 120 nm, do not refract light and therefore appear transparent to the eye.

132 The text then turns to ‘microemulsions’ and ‘micellar emulsions’, stating:

Dispersions of a liquid to such small particle sizes [~120 nm] yield microemulsions or micellar emulsions. Often, these terms are erroneously used interchangeably because such emulsions appear transparent to the human eye in daylight. In a microemulsion, disperse globules having a radius below the range of 10 to 75  nm are present.

The production of a transparent dispersion of an oil by micellization* does not result in the formation of droplets, but in the inclusion of the lipid into micelles, which may, but need not, possess spherical shapes. In terms of size, micelles have dimensions ranging from about 5 to 20 nm. To the practicing [sic] technologist, transparent emulsions, solubilized oils, micellar emulsions, and microemulsions are one and the same because they appear clear. However, solubilization in any form represents an entirely different phenomenon from that of emulsification.

(Emphasis in original)

133 The footnote to the word ‘micellization’ states that ‘[m]icelles are the result of self structuring of surface active materials in order to reach a state of minimum energy...’. Jurox argued that since micellization does not, according to this text, result in the formation of droplets, it is not within either of its theoretical or practical definitions of an emulsion. Also important, Jurox said, was the observation concerning solubilisation, being, ‘... an entirely different phenomenon from that of emulsification’ because micelles consist of solubilised surfactant.

134 Ultimately, in summary, Jurox argued that ‘Q-Drench is not, and cannot be shaken into, an emulsion. Q-Drench is a micellar solution. It is a homogenous, single phase system. It is thermodynamically stable and cannot be mechanically separated into different phases’.

135 Whilst I understand why such an emphasis was placed on the various views about the definition of an emulsion and proper classification of micellar systems, whether within the notion of an ‘emulsion continuum’ or otherwise, I do not consider that I need come to a decision on the matter. It is not contested between the parties that there is debate within the relevant scientific community about where micelles, and micellar systems, fit into the theory and practice of emulsions. The experts were generally content to admit that other experts may legitimately hold a view contrary to their own in this regard. My role is to establish whether Jurox’s product infringes Nufarm’s patent by construing that patent in accordance with the relevant legal principles. I have done this earlier in the judgment, and did not, in doing so, need to definitively decide whether a micellar system is an emulsion in a theoretical sense. Rather, I needed to decide whether the Q-Drench micellar system came within the scope of an emulsion in the sense given by the patent’s claims.

Pages 43 and 44 of the patent

136 Nufarm referred to evidence given by Professors White and Tucker in relation to statements made on page 43 of the patent, namely that ‘drenches of the present invention differ from standard suspension drenches in the way they separate’ and that ‘(a)ll drenches of the present invention readily re-emulsified with minimal agitation’. Those experts considered that the page 43 statements indicated that the patent covers only drenches requiring re-emulsification. Nufarm took issue with such an interpretation, submitting that it would unnecessarily constrict the operation of the language in the claims.

137 I consider that the references to ‘drenches of the present invention’ and ‘(a)ll drenches of the present invention’ are referable to the subsection of the examples which were unstable and not to the whole invention. That, however, by itself, does not limit the language of the claims. If it did, it would mean that the all stable emulsions were excluded from the patent, which I do not consider to be a sensible outcome. Nothing, however, turns on this point. The same reasoning applies to the submissions put by the parties in relation to page 44 of the patent.

Size of droplets

138 Jurox contended, with reference to small angle neutron scattering experiments, that the micelles in Q-Drench are extremely small particles which are ‘most probably’ cylindrical in shape with a radius at either end of less than 3nm and an overall length of less than 10nm. It claimed that the droplets in emulsions will tend to form spheres (rather than cylinders).

139 Jurox referred to a text in which the definitions of an emulsion required that the dispersed phase droplets, or globules, have a diameter of between 100nm and 10,000nm, and that a microemulsion would have a droplet diameter of 10nm to 100nm, and made the point that, under these definitions, Q-Drench would not be a microemulsion. Jurox, through Professor Tucker, also referred to a reference in the specification that, preferably, particles are almost exclusively less than 100 microns and ‘even more preferably’, less than 10 microns. Professor Tucker considered that this implied that particles should be greater than about 1 micron, which would exclude Q-Drench.

140 I am not convinced that any of these arguments relating to the size or meaning of particles take the matter very far. I consider them to be inconclusive and, in any event, have no bearing on the basis on which I have made my decision in this proceeding. The reference to the particles being ‘preferably’ smaller than 100 microns in the specification means nothing more than what it literally says. Taken alone, there is no lower or, for that matter, upper, limit, of the size of the particles. The more helpful part of the specification in interpreting the claims is the examples, which show, in my view, that a micellar system is not covered by the patent.

Merck patent

141 Jurox’s construction argument contained a second limb, namely that the definition of the term ‘emulsion’ must be limited to exclude micellar solutions such as Q-Drench in light of not only the specification language discussed above, but also the claims of a Merck patent with an earlier priority date.

142 Jurox first notes that examples 1 to 4 of the patent in suit closely resemble example 3 of the Merck patent. In addition to the similarity in composition indicated in the table set out earlier, this argument is supported by language in the Merck patent itself wherein the swollen micelles are called ‘aqueous solutions’ or ‘aqueous formulation(s)’.

143 Nufarm, quoting Kimberly-Clark Australia 207 CLR at 16 [24], agrees that the specification and claims must be ‘construed in the light of the common general knowledge and the art before ... the priority date’. It is also not disputed that the Merck patent (obtained in the US in 1983) predates the Nufarm priority date of 4 June 1999.

144 Jurox contended that the ‘Merck [p]atent and the micellar solutions described in it, including IVOMEC® [the commercial embodiment of the patent], were common general knowledge at the priority date. The references in the [Nufarm] patent to "emulsions" should be understood against that background, i.e. they do not encompass micellar solutions’.

145 Jurox argues that the evidence supports their view. In this regard they cite the testimony of their expert, Mr Shepherd. Moreover, they note that Nufarm’s expert Dr Lichti conceded on cross-examination that Merck patents generally are considered sources of knowledge for skilled addressees in the field.

146 In response, Nufarm argues that Mr Shepherd’s ‘knowledge is idiosyncratic and not representative of the common general knowledge’. It adds that Dr Lichti, while acknowledging the general importance of Merck patents, stated that he did not know of the particular Merck patent in issue. In essence, Nufarm contends that there is no or insufficient evidence to demonstrate that the Merck patent was part of the common general knowledge and art before the priority date.

147 I find Nufarm’s arguments unpersuasive. Accepting that Mr Shepherd came upon the Merck patent in the course of a particular research project and by reading a particular book, that is not a basis for suggesting that he became aware of it or obtained it by other than conventional means. Indeed, that he became aware of the Merck patent in the course of his work only strengthens the view that it must have some currency and relevance to what those in the field are doing. If, on the other hand, it were the case that Mr Shepherd became aware of the Merck patent only because, say, he has a habit of collecting large stacks of random patents for leisure reading at the beach and the Merck patent happened to be among those, then Nufarm’s ‘idiosyncratic knowledge’ argument might have some force. But that is not the case.

148 With respect to Dr Lichti, in addition to conceding the general importance of Merck patents in the field, he acknowledged to meeting with Merck executives and being aware that patent literature was a resource in the field of the instant invention. Moreover, he himself relied on several other US patents dealing with micelles to facilitate his understanding of the patent in suit. Given that both he and other testifying experts in this case (eg Dr Cook) relied upon patent literature as a common general knowledge resource for construing and understanding the patent in suit, there seems to me no principled basis for excluding the highly relevant Merck patent from that patent literature to be considered by me.

149 In my view, the evidence establishes that the Merck patent with an earlier priority date was common general knowledge before 4 June 1999.

150 Nufarm’s further contention is that ‘even assuming Nufarm was aware of the Merck patent and product, it does not follow that Nufarm considered either to be problematic and sought to limit the claims inventions [sic] to exclude microemulsions and micellar solutions’. This is true enough, but the arguments that Nufarm then proceeds to make, which all rely on the subjective thoughts or intentions of Nufarm, all miss the larger point – it does not matter whether the drafters of the patent in suit subjectively knew or did not know of the Merck patent or whether they did or did not draft their own patent in light of that knowledge. A patent is to be construed through the eyes of a hypothetical skilled addressee; it is not permissible to construe the claims by reference to subjective views.

151 Once it is established that the Merck patent was common general knowledge, the only question is how a hypothetical skilled addressee would understand the patent in suit, particularly the term ‘emulsion’ as used therein, in light of that knowledge. The answer is that, where the language of the claims and specification do not suggest a contrary reading, the addressee would tend to understand the term as referring to something other than what was already commonly known (ie macroemulsions rather than micellar systems/microemulsions). Here, the language of the patent in suit does not suggest a contrary reading. Indeed, the language of examples 1 to 4, for the reasons discussed earlier, in fact supports the same limited understanding of the term as urged by taking into account the Merck patent.

ORDER

152 I do not propose to make final orders today. I will order however that the parties confer and thereafter each file and serve short minutes of final orders reflecting the reasons in this judgment, including orders as to costs, within 14 days.

I certify that the preceding one hundred and fifty-two (152) numbered paragraphs are a true copy of the Reasons for Judgment herein of the Honourable Justice Middleton.

Associate:

Dated: 27 February 2008

Counsel for the Applicants:	B N Caine SC with G Fitzgerald
Solicitor for the Applicants:	Phillips Ormonde & Fitzpatrick Lawyers
Counsel for the Respondent:	J V Nicholas SC with A J Maryniak
Solicitor for the Respondent:	Sparke Helmore
Date of Hearing:	16-19, 23-27 July, 2-3 August 2007
Date of Judgment:	29 February 2008