Physicochemical and In-Vitro Equivalence of 15 Generic Amlodipine Besylate Tablets Marketed in Davao City, Philippines

Abstract

This study investigated the physicochemical and in-vitro equivalence of the innovator and fifteen generic brands of amlodipine besylate tablets marketed in selected community drugstores in Davao City, Philippines. The samples were coded from A to P and assayed for weight uniformity, hardness, friability, disintegration, potency, content uniformity, and dissolution using the methods described in the USP. The percentage of drug content was determined using the spectrophotometric method. The results showed that all brands conformed to the USP standard for weight uniformity, friability, and disintegration test. In addition, nine generic brands did not conform to the USP standard for the hardness test. All brands meet the USP requirement for potency with a mean content of not less than 90% and not greater than 110% of the labeled claim. Six generic brands did not conform to the USP standard for content uniformity, with acceptance values higher than the specification of 15.0%. All brands conformed to the USP standard for dissolution or percentage drug release. Further, the dissolution profile comparisons showed that 14 out of 15(93.33%) generic brands of amlodipine besylate tablets could be used interchangeably with the innovator drug. In conclusion, this study confirmed the importance of continuous monitoring of generic drugs' safety, quality, and efficacy to ensure equivalence and compliance with pharmacopeia standards and aid the prescribers’ decision-making in generic dispensing.