Abstract:
The aim of the present study was to investigate the In Vitro Equivalence Studies and compare the dissolution rate of thirteen brands of metronidazole tablets collected from retail pharmacies in Nigerian markets.This study sought to apply the BCS biowaiver requirements to assess the equivalence of commonly interchanged generic Metronidazole tablets with their innovator product in Nigeria. Solubility of active pharmaceutical ingredients (API) has always been a concern for formulators, since poor aqueous solubility may hamper development of drugs and limit bioavailability of oral products. For drug products to be interchangeably used by healthcare providers, formulation characteristics, which reflect variation within brands, batches and lots examined via dissolution profile analysis, must not show high statistical discrepancies. The quality and physicochemical equivalence of thirteen different brands of metronidazole tablets were assessed. The assessment included the evaluation of uniformity of weight, friability, breaking force /hardness test, disintegration and dissolution tests as well as chemical assay of the tablets. All the thirteen brands of the tablets passed the British Pharmacopoeia (BP) standards for uniformity of weight, two brands, MZ-3 and MZ-13 giving 29.6 minutes and 18mins respectively failed the disintegration and friability test. Six of them failed the breaking force/hardness test. There were insignificant differences in the dissolution profiles of nine (9) brands. All the brands except MZ3, MZ4, MZ10 and MZ13 released >85% of Metronidazole within 30 min showing 50.89%, 16.89%, 13.14% and 59.44% respectively in pH 1.2 and 64.80%, 20.89%, 15.80% and 48.77% in pH 6.8 respectively as such these brands should not be used interchangeably with the innovator’s brand. Only nine of the brands complied with the standard assay of active ingredients content for Metronidazole. The brands of metronidazole tablets that did not pass all the BP or USP quality specifications are regarded as not physically and chemically equivalent. This study highlights the need for constant market monitoring of new products to ascertain their equivalency to the innovator product.
