G.R. No. 126627. August 14, 2003.*
When the language of its claims is clear and distinct, the patentee is bound thereby and may not claim anything beyond them.
In 1986, Smith Kline Beckman Corporation, a foreign corporation licensed to do business in the Philippines filed before the Philippine Patent Office an application for patent over an invention entitled “Methods and Compositions for Producing Biphasic Parasiticide Activity Using Methyl 5 Propylthio-2-Benzimidazole Carbamate.” The application bore Serial No. 18989. In 1981, Letters Patent No. 145611 for the aforesaid invention was issued to petitioner for a term of seventeen (17) years. The letters patent provides in its claims that the patented invention consisted of a new compound named methyl 5 propylthio-2-benzimidazole carbamate and the methods or compositions utilizing the compound as an active ingredient in fighting infections caused by gastrointestinal parasites and lungworms in animals such as swine, sheep, cattle, goats, horses, and even pet animals.
Tryco Pharma Corporation (private respondent) is a domestic corporation that manufactures, distributes and sells veterinary products including Impregon, a drug that has Albendazole for its active ingredient and is claimed to be effective against gastrointestinal roundworms, lungworms, tapeworms and fluke infestation in carabaos, cattle and goats.