Determining the biopharmaceutical equivalency of 500 mg ciprofloxacin tablets available on the Colombian market (i.e. comparing different trademarks).Twelve commercial 500 mg ciprofloxacin tablets were obtained from drugstores and pharmacies in Colombia's four major cities. They were submitted to the following assays: HPLC identification of active ingredients, active ingredient content, dose uniformity, disintegration and dissolution tests and comparing the products' dissolution profiles to that of the innovator. The results were analyzed to establish statistically significant differences and possible inter-changeability between the products being tested.Comparative analysis of the products revealed marked differences regardingin vitrorelease of the active principle (one product failing this important quality parameter). All the products tested here complied with the official specifications for identifying and assaying the active principle, dosage unit uniformity and the disintegration test. Regarding dissolution kinetics, differences were found between formulations as some products had poor dissolution efficiency (DE) and dissolved very slowly despite complying with the Q30specification.11 products complied with USP33-NF28specifications (guidelines on specifications for impurities in antibiotics). This work has made a valuable contribution towards establishing these products' bioequivalence in the near future regarding national policy.