Aktiebolaget Hässle and Another v Triomed (Pty) Ltd

The first appellant (Aktiebolaget Hässle) is the patentee of Patent No. 87/2378, which relates to a pharmaceutical preparation containing omeprazole, a drug used to treat gastric and duodenal ulcers. The second appellant (AstraZeneca Pharmaceuticals) was licensed to use the invention. Omeprazole is unstable and degrades in acidic solutions, so the invention involves encapsulating it in an enteric coating to protect it while passing through the stomach. The invention includes an alkaline core containing omeprazole, a subcoating layer between the alkaline core and the outer enteric coating to prevent dissolution from within, and an outer enteric coating. The respondent (Triomed) imported and distributed a pharmaceutical preparation called Ulzec in 10g and 20g doses. The appellants alleged that Ulzec infringed their patent and applied to the Commissioner of Patents for interim relief to restrain the respondent from distributing Ulzec. The Commissioner (Southwood J) found that Ulzec did not infringe the patent and dismissed the application. The key dispute was whether claim 1(b) of the patent required the subcoating layer to consist of more than one excipient or compound. Ulzec's alkaline core was subcoated with a single compound (polyvinyl pyrrolidone).

• Whether the use of plural words 'excipients' and 'compounds' in claim 1(b) of the patent specification required the subcoating layer to consist of more than one different excipient or compound
• Whether a patent specification should be given a purposive construction or a purely literal construction
• Whether Ulzec, which used a single compound in its subcoating layer, infringed Patent No. 87/2378
• What constitutes the essential elements or 'pith and marrow' of a patented invention

The appeal was upheld with costs, including costs of two counsel. The order of the Commissioner of Patents was set aside. The Court declared that the respondent infringed claim 1 of Patent No. 87/2378 by importing, making, disposing of or offering to dispose of its Ulzec products. The application for temporary interdict was remitted to the Commissioner of Patents in accordance with the Court's earlier order of 17 May 2002.

A patent specification must be given a purposive construction to identify the essential elements of the invention, rather than a purely literal construction involving meticulous verbal analysis of individual words. The enquiry is whether persons skilled in the art would understand that strict compliance with particular descriptive words in a claim was intended to be essential to the invention. When words in a patent claim are ambiguous or their meaning is doubtful when read in context, the body and title of the specification may be consulted to ascertain their meaning. The use of plural words in a patent claim does not necessarily exclude singular applications where: (1) the claim is indifferent to the specific composition provided functional requirements are met; (2) other claims in the specification suggest singular applications are included; (3) the body of the specification and examples demonstrate singular applications; and (4) requiring plurality would be inconsistent with the overall invention as described. In such circumstances, plural words may refer to quantity rather than variety. An article infringes a patent if it falls within the ambit of the properly construed claims, and differences that are not matters of substance will not place it outside the scope of the claims.

The Court noted that to the extent an obiter dictum in Nampak Products Ltd v Man-Dirk (Pty) Ltd 1999 (3) SA 708 (SCA) suggested that purposive construction might only be called in aid to construe an ambiguous claim, this was not supported by earlier decisions of the Court and was not correct. Nugent JA clarified that purposive construction is merely an approach to construction aimed at establishing what was meant in a particular context, not a tool reserved only for resolving ambiguities. The Court also discussed the meaning of the word 'comprises' in patent claims, noting that it may be used synonymously with 'includes' according to modern usage and as accepted in United States patent cases, though the Court found it unnecessary to definitively decide this point for purposes of the case.

This case is significant in South African patent law for its application and reinforcement of the principle of purposive construction of patent specifications. It emphasizes that courts must look beyond literal textual interpretation to identify the essential features or 'pith and marrow' of an invention. The judgment clarifies that the use of plural words in a patent claim does not automatically exclude singular applications where the context of the invention as a whole indicates otherwise. The case demonstrates the importance of reading patent claims in the context of the entire specification, including other claims, the body of the specification, and examples provided. It reaffirms the approach adopted from English law (Catnic Components) and developed in earlier South African cases like Letraset, Multotec Manufacturing, Stauffer Chemical, and Sappi Fine Papers. The decision provides important guidance on how courts should balance literal wording against the inventor's apparent intentions and the functional requirements of the invention when determining patent infringement.