HPLC method development and in vitro dissolution kinetics of amlodipine tablets under biowaiver conditions

Abstract

A biowaiver means that in vivo bioavailability and/or bioequivalence studies may be waived (not considered necessary for product approval). Instead of conducting expensive and time consuming in vivo studies, a dissolution test could be adopted as the surrogate basis for the decision as to whether the two pharmaceutical products are equivalent. The biowaiver approach based on BCS is intended to replace bioequivalence in vivo studies. The aim of the study was to study dissolution kinetics of amlodipine tablets in order to assess their equivalence under conditions in vitro according to the biowaiver. The study of dissolution kinetics of drugs in the form of amlodipine tablets has been carried out in accordance with the requirements of the “biowaiver” procedure, the recommendations of the SPhU and the WHO requirements in order to assess the possibility of replacing the pharmacokinetic studies in vivo by tests in vitro. The possibility to use the recommendations of the "biowaiver" procedure for the registration of generics amlodipine tablets has been found. The studies conducted have shown that amlodipine can be referred to class І of the biopharmaceutical classification system, i.e. substances with a high biopharmaceutical solubility and a high penetration rate. It will allow conducting comparative studies in vitro to confirm the equivalence of drugs. The evaluated amlodipine drugs fulfill biowaiver criteria for drugs containing BCS Class I active pharmaceutical ingredients. Both drugs are “rapidly dissolving,” both meet the criteria of dissolution profile similarity, f2 (i.e., the dissolution profile of the test product is similar to that of the reference product in pH 1.2, 4.5, and 6.8 buffers using the paddle method at 75 rpm), and both are considered to be in vitro equivalent without in vivo evaluation. The proposed chromatographic methods are simple, rapid and accurate for the determination of amlodipine in pharmaceutical dosage forms and can be used for routine quality control of drugs and in vitro dissolution study.