Court emphasises importance of patent specifications in construction of claims

Court emphasises importance of patent specifications in construction of claims

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

Facts of the case

The Federal Court has handed down a decision dismissing allegations of patent infringement brought against Jurox Pty Ltd (“Jurox”) by Nufarm Ltd (“Nufarm”). The alleged infringement concerned Nufarm’s Australian Innovation Patent No. 2003101020 (“the patent”) which discloses an oral drench formulation for controlling intestinal parasites, primarily in sheep.

Nufarm alleged that Jurox’s oral drench product Q-Drench infringed claims 1 to 5 of the patent. Jurox cross-claimed alleging the patent was invalid and a separate trial was ordered to determine the issue of validity. The primary issue to be considered was therefore whether or not Q-Drench was an ‘emulsion’ consisting of an ‘organic liquid phase’ and an ‘aqueous phase’ as claimed in the patent or was capable of being ‘shaken or agitated into the form of an emulsion’ as required by the claims of the patent. Jurox submitted in defence that Q-Drench was in fact a micellar solution.

Expert evidence and claim construction

Both parties gave expert evidence as to the exact meaning of the terms ‘emulsion’ and ‘phase’ with Nufarm contending that the term ‘emulsion’ is a broad term which encompasses macroemulsions, coarse emulsions (having large droplet) and microemulsions (having small droplets), swollen micellar systems and micellar systems. Jurox, on the other hand, argued that the term ‘emulsion’, as used in claim 1, should be construed to cover only macroemulsions and to exclude micellar solutions such as Q-Drench. In light of the conflicting expert evidence Middleton J found that the terms had more than one meaning and were lacking in clarity so turned to the body of the specification, in particular to the examples, to determine how the skilled addressee would interpret the scope of the terms and hence the scope of the claims.

The decision

Middleton J focussed his discussion on Examples 1 to 4 which, as conceded by Nufarm, described micellar formulations similar to Q-Drench. It was accepted by Nufarm that the work on the ‘completely aqueous formulations’ of Examples 1 to 4 ceased. His Honour held that these examples, whilst not described as comparative, were only included to describe the path of discovery of the invention and did not embody the invention itself, and that when read in light of the language of the claims indicated that any attempt to claim a micellar formulation was abandoned. Accordingly, his Honour found that QDrench, whilst similar to the four examples, did not possess all the essential elements of claim 1 (and thus the dependant claims) and therefore did not infringe the patent.

Commentary

The decision confirms that in cases where a term is not clearly defined and is capable of having more than one meaning, the Court will look to the body of the specification to determine the context in which the term is used. It is therefore essential to ensure that any terms used in the claims that do not have a clear and plain meaning to a skilled person are defined in the body of the specification so that such terms are more likely to be construed in a manner favourable to the patentee.

Further, it is critical that when examples are used they should either support the claims or be clearly defined as comparative examples.