Comparative In Vitro Dissolution Profile of Commercial Azithromycin Dihydrate 500 mg Tablet Preparations in the Philipppines

This study seeks to compare the in vitro multi-point dissolution profiles between 3 off-patent products azithromycin dihydrate 500 mg and the innovator product. The paddle-type dissolution apparatus was used. This was rotated at a speed of 50 rpm using 0.1-N HCl as media. Random samples were withdrawn after certain time points and assayed for azithromycin dihydrate. Comparision between test samples and the innovator product was done by computing their similarity (f 1 ) and disimilarity (f 2 ) factors and by fitting them to various kinetics of drug release during dissolution. Test samples 1 and 3 were comparable to the innovator product because they complied with f 1 and f 2 specifications. Test sample 2, however, gave higher f 2 values making it non-equivalent with the innovator product. The Higuchi and Korsmeyer-Peppa kinetics of drug release characterized most of the dissolution profiles. This study showed that test samples 1 and 3 are equivalent with the innovator products in terms of comparative in vitro dissolution profiles where extra-Fickian release behaviors was exhibited by all the preparations.