IN-VITRO DISSOLUTION TESTING FOR THERAPEUTIC EQUIVALENCE OF METRONIDAZOLE IMMEDIATE RELEASE TABLETS AVAILABLE IN KARACHI, PAKISTAN

Metronidazole is a class I drug in biopharmaceutics classification system (BCS) and widely used in Pakistan, various available brands in local markets along with innovator brand to serve a large population. In-vitro dissolution testing can be used as waiver for in-vivo bioequivalence studies of generic brand interchangeability for Class I drugs i.e., highly soluble and highly permeable. The objective of the study was to determine immediate release tablet dosage form of metronidazole to fulfil the requirements of 85% drug release in pH 1.2, 4.5 and 6.8 recommended by WHO. In this study physicochemical quality attributes, price comparison and dissolution studies were performed on three available brands of metronidazole 400 mg, one of them is innovator brand and the two others are test brands. The dissolution profiles were compared by using similarity factor (f₂) that were analyzed by UV spectrophotometer at 278 nm wavelength. The test brands were very cheap in cost as compared to innovator brand but both the test brand were failed the dissolution test in all mediums and only innovator brand showed 85% drug release within 30 minutes. The study suggested test brands are not equivalent or similar to innovator brand. In-vivo bioequivalence studies are thus needed for test brands to strengthen this in-vitro finding.