Evaluation of In Vitro Equivalence for Tablets Containing the Poorly WaterSoluble Compound Atorvastatin

Abstract

This paper describes the evaluation of the in vitro equivalence of tablets containing a poorly water-soluble compound, atorvastatin, marketed in Bangladesh under biowaiver conditions. Drug release was compared with that of a reference product. The in vitro equivalence test was carried out in three different media (pH 1.2, pH 4.5, and pH 6.8). Test results were subjected to statistical analysis to compare the dissolution profiles. Model-independent approaches of difference factor (f 1 ), similarity factor (f 2 ), and dissolution efficiency (%DE) were employed. Dissolution profiles of test and reference (innovator) atorvastatin are equivalent at pH 6.8 without statistical treatment. The test products are equivalent at pH 4.5 (f 1 < 15 and f 2 > 50) and not equivalent at pH 1.2 (f 1 > 15 and f 2 < 50). Other general quality parameters of these tablets (e.g., weight variation, crushing strength, friability, and disintegration time) were also determined according to established protocols, and test results were within limit.