Dissolution test and comparison of in vitro dissolution profiles of amlodipine tablets (reference, generic and similar) marketed in Bahia, Brazil using factorial design

Amlodipine, used to treat arterial hypertension1, requires essential pharmacopoeial testing for quality assurance2. Objective: To evaluate the dissolution kinetics of amlodipine tablets. Methods: Tests were performed3 (weight uniformity, friability and disintegration); a dissolution method was developed, using factorial design 23 (rotation, HCl concentration and medium volume); within 30 min at 37±0.5 °C and USP apparatus 2 (paddle)4 and to validated according to RDC 166/201755. Results: Analysis of variance (ANOVA) and Paretto (Statistica7.0) showed that variables did not significantly affect drug release; and minimum conditions (50rpm and 500mL of 0.001mol L-1 HCl) were used to delineate dissolution profiles (1-60min)4 in different media: distilled water (pH = 6.03); acetate buffer (pH = 4.5) and borate buffer (pH = 8.0), with major release of amlodipine in acidic medium. Dissolution efficiencies were calculated: reference (73.6%), generic (61.3%) and similar (59.1%). Conclusion: Amlodipine tablets complied with pharmacopoeial tests, with method fast, linear and accurate.