Criticality of construction affirmed
Nufarm Ltd v Jurox Pty Ltd  FCAFC 180 (11 November 2008)
Facts of the case
At first instance
The primary issue considered at first instance was whether or not Q-Drench was an ‘emulsion’ comprising 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. In light of conflicting expert evidence the primary judge, Middleton J, 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. Middleton J focussed his discussion on examples 1 to 4 which, as agreed by both parties, described micellar formulations similar to Q-Drench and held that these examples were only included to describe the path of discovery of the invention and did not embody the invention itself. Accordingly, it was found that whilst Q-Drench was a formulation within those examples it did not infringe the patent.
n the appeal to the Full Federal Court Nufarm alleged that whilst the primary judge found the basis of the invention was the use of a dual personality carrier system his Honour failed to take this into account in his construction of the claims. Specifically, Nufarm asserted that the word ‘emulsion’ as used in the claims should be read as including macroemulsions, microemulsions and micellar solutions, including ‘swollen micellar solutions’ of which Q-Drench was one. Furthermore, Nufarm alleged that His Honour erred in his conclusion that because examples 1 to 4 were described as ‘completely aqueous formulations’ a skilled addressee would have understood there to be a ‘fundamental transition’ in the nature of the formulations after example 4. In this regard, Nufarm contended that even though the specification noted that work stopped on the formulations of examples 1 to 4, the cessation was only as a result of poor longterm stability and the formulations were still representative of the invention, and therefore a skilled addressee would not have understood that the patentee had abandoned or disclaimed micellar solutions or macroemulsions. Accordingly, Nufarm insisted that there was no reason to exclude examples 1 to 4 from the scope of the claimed monopoly.
Whilst Nufarm placed much emphasis in the appeal on the categorisation of the formulations of the examples into micelles, swollen micelles, microemulsions and macroemulsions, the Court stressed that this did not define the primary judge’s decision. Rather, the Court contended that central to the appeal was what Middleton J did and did not decide. It was held that at first instance His Honour’s decision was not to choose between the conflicting expert opinions in the abstract but to decide whether the Q-Drench micellar system came within the scope of an emulsion in a sense used in the claims of the patent based upon the construction of the specification.
The Full Federal Court concurred with the primary judge’s analysis based upon the construction of the specification, and held that the patent was not infringed because, when viewed in light of the expert evidence, the construction of claims demonstrated that examples 1 to 4, and therefore Q-Drench, lacked the essential elements of the claims.
The decision reaffirms that where a term is ambiguous, the Court will look carefully at the body of the specification to determine the context in which the term is used. It is therefore a timely reminder to ensure that any technical terms used in the claims that are not readily understood to a skilled person should be clearly defined in the body of the specification, and that when examples are used they should either support the claims or be clearly defined as comparative examples.