RESUMEN
BACKGROUND: There is currently a lot of concern about the quality and therapeutic effectiveness of Mexican pharmaceutical products, and considerable price differences between alternative products containing the same active principle. OBJECTIVE: To establish whether four Mexican drug products, a high price and three lower-cost branded drug products containing sodium naproxen (550 mg immediate release tablets) have equivalent, and consistent pharmaceutical qualities. METHODS: The four products were acquired in Mexico city. Assay for sodium naproxen, content uniformity, disintegration time and dissolution tests were performed according to USP procedures. Drug dissolution profiles were compared using a similarity factor (f(2)). RESULTS AND DISCUSSION: All of the tested products met pharmacopeial quality standards with respect to their active pharmaceutical content and a released drug percentage >70% in 45 min. Lot-to-lot lack of similarity between drug dissolution profiles was observed for two of the products tested. CONCLUSION: There was no significant differences in the quality of the pharmaceutical products tested when judged by the USP pharmaceutical quality standards. However, some differences were observed in the dissolution profiles of the brands tested. Whether these differences are clinically meaningful requires in vivo bioequivalence studies.