Physicochemical equivalence evaluation of some piroxicam capsule brands in Nigeria.

Comparative chemical and pharmaceutical equivalence study on ten brands of piroxicam capsules was carried out. The aim of the study was to determine whether the brands are comparable with each other on the basis of their physico-chemical properties. The chemical and pharmaceutical equivalences of ten brands of piroxicam capsules were assessed by evaluating the uniformity of weight, dissolution rate, content identification and the chemical assay of the capsules. All the ten brands complied with British Pharmacopoiea standard for uniformity of weight. The thin layer chromatographic test for content identification showed that nine of the brands contain only piroxicam while one brand contains an additional compound apart from the labeled piroxicam. The ultraviolet procedure for content identification showed that only two brands complied with the official specification. Five brands complied with specification for the content assay of the active ingredient. However, only two brands complied with the official specification of 70% w/v dissolution at 45 minutes. The result obtained from this study showed that only the innovator brand meets all the specifications. Moreover, only five of the other brands can be regarded as chemical equivalent of the innovator. The result obtained in this study underscores the need for registration and post market surveillance of products circulating in the drug market.