EQUIVALENCE OF TWO GENERIC BRANDS OF AMLODIPINE BESYLATE UNDER BIOWAIVER CONDITIONS

Quality of generic medicines should be comparable with the innovator brand and therefore interchangeable with the innovator. Affordable quality tests that assure pharmaceutical and therapeutic equivalence of generics are needed, so that product selection of low priced generics by health practitioner is objective. Without appropriate tests to assess bioequivalence (BE) in cost effective manners, maximum cost savings accruable to generic use may not be realized, because cheap generics are often associated with poor quality. Based on Biopharmaceutics Classification System (BCS), dissolution testing can be used as surrogates for in vivo BE studies (biowaiver). The study objective was to compare dissolution profiles of two generics of a BCS class I drug (amlodipine) with innovator amlodipine under biowaiver conditions. Method: Assessment of physical parameters which include, uniformity of weight, hardness, friability and disintegration test were done according to British Pharmacopeia (BP) 2007 requirements. Chemical assay was carried out using a validated UV spectrophotometric method. The dissolution profile of Amlodipine tablets were evaluated in three media (pH 1.2, buffer pH4.5 and 6.8) using US Pharmacopoeia dissolution apparatus II. Result: All the formulations conformed to B.P 2007 pharmacopoeial tests for tablets. The percentage purity of the three brands was within the range of 90 – 110% general tolerance level for tablet formulation in B.P. The results showed that none of the products met biowaiver criteria for very rapidly dissolving tablets. F2 calculation was used to assess dissolution profile similarity. A generic brand sample B was comparable with the innovator brand in all the media (f 2 ≥50) while the sample A has f 2≤50 in one media. Conclusion: To make objective decision about generic product selection, pharmacists and other health practititoners need adequate information on suitability of generic for substitution from national regulatory bodies.