Brief Summary

Patent — Infringement — Construction of patent claims — The first appellant, Aktiebolaget Hässle, and the second appellant, AstraZeneca Pharmaceuticals (Pty) Ltd, sought to restrain the respondent, Triomed (Pty) Ltd, from distributing a pharmaceutical preparation, Ulzec, which they alleged infringed their patent concerning an oral formulation of omeprazole. The Commissioner of Patents found that Ulzec did not infringe the patent, primarily due to the composition of its subcoating layer. The legal issue revolved around the purposive construction of the patent claims, specifically whether the requirement for multiple excipients in the subcoating layer was essential for infringement. The court held that the essence of the invention did not necessitate multiple excipients, and thus, the respondent's product did infringe the patent.

Comprehensive Summary

Summary of Judgment

1. Introduction

This was an urgent interlocutory appeal in patent infringement proceedings, arising from an application for interim (temporary) interdictory relief pending the determination of an action for final relief. The appeal was heard by the Supreme Court of Appeal of South Africa from a decision of the Commissioner of Patents (Southwood J).

The parties were Aktiebolaget Hässle (the patentee and first appellant) and AstraZeneca Pharmaceuticals (Pty) Ltd (the licensee and second appellant) as appellants, and Triomed (Pty) Ltd as respondent. The respondent imported and distributed a pharmaceutical product alleged to infringe the patent.

In the court below, several issues were raised, but the Commissioner decided only the issue of infringement and dismissed the interim-interdict application on the basis that the respondent’s product did not infringe the patent. Leave to appeal was granted. On appeal, the Supreme Court of Appeal directed (under Rule 11) that the appeal would be confined to infringement and that, if the appeal succeeded, the matter would be remitted to the Commissioner to determine the remaining issues relevant to interim relief.

The general subject-matter concerned the construction of patent claims (in particular purposive construction) and whether a specific pharmaceutical formulation (Ulzec) fell within the scope of claim 1 of Patent No. 87/2378, relating to an enteric-coated oral preparation of omeprazole with a functional subcoating layer designed to protect the active ingredient and improve stability and delivery.

2. Material Facts

The patent in issue, Patent No. 87/2378, related to a pharmaceutical preparation containing omeprazole, a potent inhibitor of gastric acid secretion used in treating ulcers. Omeprazole is relatively unstable and degrades in acid solutions. For oral administration, the drug must be formulated to pass through the stomach without exposure to gastric acid and to be released in the proximal small intestine, where conditions allow it to disperse and be absorbed.

The specification described a formulation strategy in which the alkaline omeprazole-containing core is protected by an outer enteric coating that resists dissolution in the stomach but dissolves in the intestine. However, enteric coatings commonly used are acidic, and omeprazole’s storage stability is improved by mixing it with an alkaline reacting compound. The specification further described a problem: moisture may diffuse through the enteric coating during gastric residence, partially dissolving the alkaline core near the coating; an alkaline solution can then form beneath the enteric coating and dissolve it from within. The invention addressed this by inserting a subcoating barrier layer between the alkaline core and the enteric coating.

It was common cause that the respondent imported and distributed a product known as Ulzec (in 10g and 20g doses), and that Ulzec’s alkaline core was subcoated with a single compound, namely polyvinyl pyrrolidone (PVP), which is a water-soluble, film-forming polymer.

The dispute on infringement was narrow and turned on the proper construction of paragraph (b) of claim 1, which referred to “one or more inert reacting subcoating layers comprising tablet excipients … or polymeric, water soluble, filmforming compounds …”. The respondent contended that the use of plural words “excipients” and “compounds” meant that claim 1 essentially required the subcoating layer(s) to be constituted by more than one excipient or compound. Because Ulzec used only a single subcoating compound (PVP), the respondent argued that Ulzec fell outside the claim.

The Commissioner accepted the respondent’s literal reading of the plural terms and concluded that Ulzec did not infringe. The appeal was directed solely at whether that conclusion on infringement was correct.

3. Legal Issues

The central legal questions were, first, how claim 1 of the patent should be construed, and second, whether the respondent’s product, Ulzec, as formulated, fell within the ambit of claim 1 as properly construed.

More specifically, the determinative interpretive issue was whether, in the context of the claim and specification, the plural terms “tablet excipients” and “filmforming compounds” in claim 1(b) required the subcoating to contain at least two different excipients/compounds, or whether the claim encompassed a subcoating consisting of only one suitable excipient/compound that met the functional requirements.

The dispute was primarily one of law, namely the proper construction of the patent claim using the interpretive approach mandated by South African patent jurisprudence, and the subsequent application of that construction to the undisputed formulation features of Ulzec to determine infringement.

4. Court’s Reasoning

The court approached the issue by reaffirming the established principle that infringement is determined by comparing the allegedly infringing article or process with the words of the claims, properly construed. In doing so, the court reiterated that the law focuses on the substance or essence of the invention and does not allow the “pith and marrow” to be appropriated through insubstantial variation. The evaluation of what constitutes the substance or essence is a matter for judicial “good sense” within the infringement enquiry.

A central feature of the court’s reasoning was that patent claims must be given a purposive construction, rather than a purely literal or overly textual construction. The court adopted the approach that claim language is addressed to persons skilled in the art, and the question is whether such persons would understand strict compliance with a particular word or phrase to have been intended by the patentee as an essential requirement, such that any variant would fall outside the monopoly even if it had no material effect on how the invention worked. The court cautioned against “peering too closely” at isolated words in a claim, because an excessively textual approach may overlook an infringement that takes the substance of the invention.

Applying those principles, the court considered the respondent’s contention that the plural form of “excipients” and “compounds” necessarily imported a requirement of multiple different substances in the subcoating. The court accepted that, on a strictly literal reading, plural language might suggest at least two excipients or compounds and noted that the Commissioner had adopted this literal meaning. However, the court held that the proper question was what was intended to be essential in the context of the invention as a whole.

The court then reasoned from the function of the subcoating as described in the claim and specification. The subcoating’s purpose was to form an effective but water-soluble barrier between the alkaline core and the enteric coating. The court observed that claim 1 did not insist upon or specify particular chemical compositions for the subcoating; instead, it described the subcoating in functional terms (water-soluble or rapidly disintegrating excipients or polymeric water-soluble film-formers, optionally with buffering alkaline compounds). From this, the court inferred that the inventor regarded the particular composition of the subcoating as immaterial, provided that it met the functional characteristics. On that premise, the court found it difficult to see why the patentee would have intended it to be essential that there be two or more different excipients or compounds. If any mixture of two would suffice, the claim’s apparent indifference to composition undermined the idea that multiplicity of different substances was an essential element.

The court’s doubt that multiplicity was essential increased when it read claim 1 together with claims 3 and 4, which incorporated claim 1’s elements. Claim 3 contemplated that “the subcoating comprises two or more sub-layers,” while claim 4 stated that a preparation according to claim 3 (thus having at least two sub-layers) may have subcoating that “comprises” hydroxypropyl methylcellulose, hydroxypropyl cellulose, or polyvinylpyrrolidone. The court considered that if “comprises” in claim 4 were intended to mean “consists of,” then claim 1 could not have been intended to exclude a subcoating consisting of only one compound, because that would render claim 4 internally inconsistent. Although the respondent argued that “comprises” could be used synonymously with “includes,” the court found it unnecessary to resolve definitively the precise meaning of “comprises” in claim 4; what mattered was that, read contextually, the structure of the dependent claims did not support a strict multiplicity requirement in claim 1.

Having found that the claim language (when read contextually) created at least considerable doubt as to whether the plural words imposed an essential requirement of multiple excipients/compounds, the court turned to the established rule that where claim words are ambiguous (in the sense that their meaning is doubtful or not reasonably clear in context), the body and title of the specification may be used to ascertain a reasonably certain meaning.

Upon examining the body of the specification, the court found no suggestion that the subcoating must consist of more than one excipient or compound; if anything, it suggested the contrary. The specification described the subcoating as consisting of “one or more water soluble inert layers” and stated that the subcoating material is chosen among pharmaceutically acceptable water-soluble inert compounds or polymers used for film-coating. Crucially, the court relied on the examples in the specification that purported to describe the invention “in detail,” observing that in many examples the subcoating layer consisted of a single compound (often dissolved in distilled water or ethanol). This was, in the court’s view, inconsistent with construing claim 1 as confined to subcoatings containing at least two different excipients or compounds.

In light of the purposive approach, the functional role of the subcoating, the context of claims 3 and 4, and the body of the specification including its examples, the court concluded that the plural words in claim 1 were not intended to make it an essential element that the subcoating contain more than one excipient or compound. Instead, the court construed the plural as referring to a quantity of excipient/compound rather than requiring multiple different kinds. On that construction, Ulzec’s use of a single subcoating compound (PVP) did not avoid the claim. The court accordingly held that the respondent’s product infringed claim 1, and that the interim-interdict application should not have been dismissed on the ground of non-infringement.

5. Outcome and Relief

The Supreme Court of Appeal upheld the appeal and set aside the order of the Commissioner of Patents.

The court granted declaratory relief that the respondent, by importing, making, disposing of, or offering to dispose of its Ulzec products, infringes claim 1 of Patent No. 87/2378.

Consistent with the earlier direction that only infringement would be determined on appeal, the court remitted the application for the temporary interdict to the Commissioner of Patents for determination of the remaining issues relevant to interim relief.

The respondent was ordered to pay the appellants’ costs of appeal, including the costs occasioned by the employment of two counsel.

Cases Cited

R v Secretary of State for the Home Department, ex parte Daly [2001] UKHL 26; [2001] 3 All ER 433 (HL) at 447a.

Letraset Ltd v Helios Ltd 1972 (3) SA 245 (A) at 274G-H.

Multotec Manufacturing (Pty) Ltd v Screenex Wire Weaving Manufacturers (Pty) Ltd 1983 (1) SA 709 (AD) 722A-D.

Stauffer Chemical Co and Another v Safsan Marketing and Distribution Co (Pty) Ltd and Others 1987 (2) SA 331 (A) 343A-344D.

Sappi Fine Papers (Pty) Ltd v ICI Canada Inc (Formerly CIL Inc) [1992] ZASCA 58; 1992 (3) SA 306 (AD) 319I.

Catnic Components Limited and another v Hill and Smith Limited [1982] RPC 183 (HL) at 242.

Gentiruco A.G. v Firestone S.A. (Pty) Ltd 1972 (1) SA 589 (A) 614B-C and 615F-G.

Nampak Products Ltd and Another v Man-Dirk (Pty) Ltd 1999 (3) SA 708 (SCA) at 714A.

Fundstrust (Pty) Ltd (in Liquidation) v Van Deventer 1997 (1) SA 710 (A) at 726H-727B.

Loryan (Pty) Ltd v Solarsh Tea and Coffee (Pty) Ltd 1984 (3) SA 834 (W) at 846G ad fin.

Monsanto Co v MDB Animal Health (Pty) Ltd (formerly MD Biologics CC) 2001 (2) SA 887 (SCA) at 892B-C.

In re Bertsch 56 USPQ 379 at 384.

H.K. Porter Company, Inc v The Gates Rubber Company 187 USPQ 692 at 715.

Legislation Cited

No legislation was cited by name in the extracted text of the judgment.

Rules of Court Cited

Rule 11 (as invoked by the Supreme Court of Appeal to confine the appeal to infringement and provide for remittal if successful).

Held

The court held that purposive construction governs the interpretation of patent claims, requiring identification of the essential elements of the invention in context rather than by strict literalism. On a purposive reading of claim 1 of Patent No. 87/2378, the plural references to “excipients” and “compounds” in the subcoating description were not intended to require more than one different excipient/compound; they referred to a quantity of suitable excipient/compound meeting functional requirements.

Accordingly, a pharmaceutical preparation whose subcoating consists of a single water-soluble film-forming polymer (polyvinyl pyrrolidone) could fall within claim 1. On the undisputed facts regarding Ulzec’s formulation, the respondent’s importation and distribution of Ulzec infringed claim 1. The appeal was upheld, the Commissioner’s non-infringement finding was set aside, infringement was declared, and the interim-interdict application was remitted for determination of remaining issues. Costs were awarded against the respondent, including costs of two counsel.

LEGAL PRINCIPLES

Purposive construction is the proper approach to construing a patent specification and its claims. The interpretive task is to determine, from the perspective of persons skilled in the art, what the patentee intended to be the essential features of the invention, rather than to apply an overly literal analysis of individual words divorced from context.

Infringement is determined by comparing the allegedly infringing product or process with the claims as properly construed. Variations that do not take the alleged infringer outside the substance or “pith and marrow” of the invention will not necessarily avoid infringement, and determining what is essential is a matter for judicial evaluation informed by the context and purpose of the invention.

Where the words used in a claim are ambiguous in context, the body (and title) of the specification may be consulted to establish a reasonably certain meaning. The specification’s description of the invention and its examples may be used to resolve doubt about whether a feature expressed in a particular grammatical form (including the plural) was intended to operate as an essential limitation excluding otherwise functionally equivalent embodiments.

Aktiebolaget Hassle and Another v Triomed (Pty) Ltd (63/2002) [2002] ZASCA 103; [2002] 4 All SA 138 (SCA) (12 September 2002)