Quality assessment of samples of generic and similar aspirin tablets (500 mg) marketed in Brazil

The interchangeability between a generic and the respective reference drug is based on the concept of therapeutic equivalence between them, usually provided by evidence of pharmaceutical equivalence, bioequivalence, Good Manufacturing Practices (GMP), and quality control. This study aimed to evaluate the pharmaceutical equivalence between four brands of 500 mg aspirin tablets (two generic, G, and two similar, S) in relation to the reference drug (Aspirin® Bayer, R). The following tests were performed: uniformity of mass; friability; disintegration time; hardness; limit of free salicylic acid; assay; uniformity of dosage units; dissolution; identification; and dissolution profile. The similar drug 2 (S2) is out of specifications in the tests of limit of free salicylic acid, friability and assay. The drug S1 was not approved in the limit test. Moreover, the results from the dissolution profile (graphic and f2 factor) showed that the six test drugs were not pharmaceutically equivalent to the R.