Aktiebolaget Häsle and Another v Triomed (Pty) Ltd

• Jurisdiction: South Africa
• Judge: Hefer Ap, Harms JA, Farlam JA, Navsa JA and Nugent JA
• Judgment Date: 12 September 2002
• Citation: 2003 (1) SA 155 (SCA)
• Docket Number: 63/2002
• Hearing Date: 19 August 2002
• Counsel: P Ginsburg SC (with C J van der Westhuizen) for the appellants. L C Bowman SC (with J N Cullabine) for the respondent.
• Court: Supreme Court of Appeal

Nugent JA:

[1] 'In law', remarked Lord Steyn in R v Secretary of State for the Home Department, ex parte Daly, [1] 'context is everything'. And so it is when it comes to construing the language used in documents, whether G the document be a statute, or a contract, or, as in this case, a patent specification.

[2] Patent No 87/2378, which is in issue in this appeal, relates to a pharmaceutical preparation containing omeprazole. Omeprazole is a potent inhibitor of gastric acid secretion, which makes it useful in H the treatment of gastric and duodenal ulcers. It is relatively unstable, however, and degrades rapidly in the presence of acid solutions. If the drug is to be administered orally it must be prepared in a form that enables it to pass through the stomach without having contact with the acidic stomach fluids, so that it can be delivered intact to the proximal part of the small intestine where the I environment is suitable for the drug to be dispersed.

Nugent JA

[3] The first appellant is the patentee and the second appellant has been licensed to use the invention. The respondent imports and A distributes a pharmaceutical preparation known as Ulzec, in 10 g and 20 g doses, which is alleged by the appellants to infringe the patent. The appellants applied to the Commissioner of Patents, as a matter of urgency, for interim relief aimed at restraining the respondent from distributing Ulzec pending the outcome of an action for final B relief. Several issues were raised in those proceedings but the Commissioner (Southwood J) found it necessary to deal with only one of them - he found that Ulzec does not infringe the patent and on that ground alone the application was dismissed. Leave to appeal having been granted by the Commissioner, this Court directed in terms C of Rule 11 of the Uniform Rules of Court that the appeal would be confined to the issue of infringement and that if the appeal were to succeed the application would be remitted to the Commissioner for the remaining issues to be dealt with.

[4] The aim of the invention, according to the patent specification, is to enable an oral dose of omeprazole to be delivered D intact to the proximal part of the small intestine, there to be rapidly dispersed so that it can be absorbed through the wall of the intestine into the bloodstream. In order for the drug to pass through the stomach without having contact with the acidic stomach fluids it is encapsulated in an enteric coating that is resistant to dissolution in the stomach but dissolves in the proximal part of the intestine. E Enteric coatings that are in common use, however, are themselves acidic, which would ordinarily cause the drug to deteriorate while in storage, but the storage stability of the drug is enhanced if it is mixed with an alkaline compound. It was found that when such an alkaline core is enteric-coated some diffusion of moisture through the F coating occurs during the time that the dosage resides in the stomach, which dissolves part of the core in the proximity of the coating with the result that an alkaline solution forms under the enteric coating and dissolves it from within. That problem is overcome, according to the invention, by coating the alkaline core with a substance that forms G a barrier between the alkaline core and the outer enteric coating. It is the composition of that subcoating layer that lies at the centre of the present dispute.

[5] The invention is claimed as follows in claim 1 of the patent specification (some of the remaining claims are of secondary relevance to this appeal and I will return to them later in this judgment): H

'1.

An oral, pharmaceutical preparation in the form of enteric coated tablets or pellets, containing omeprazole as the active ingredient characterized in that it is composed of:

(a)

alkaline core material containing omeprazole together with an alkaline reacting compound, or an alkaline salt of omeprazole optionally together with an alkaline reacting compound, and I

(b)

on said alkaline core material one or more inert reacting subcoating layers comprising tablet excipients which are soluble or rapidly disintegrating in water, or polymeric, water soluble, filmforming compounds, optionally containing pH-buffering, alkaline compounds between the alkaline core material and J

Nugent JA

(c)

an outer layer, which is an enteric coating.' A

[6] The dispute falls within a narrow compass. Paragraph (b) of claim 1 envisages the active...