Comparative Bioavailability Assessment of Four Brands of Ciprofloxacin Tablets Marketed in South-East Nigeria

Objective: of study: This study evaluated the relative bioavailability of four brands of ciprofloxacin (500mg) tablets marketed in Southeast, Nigeria using an in vivo approach. Methods: : The bioavailability study was carried out on twelve healthy male rabbits which were given a single dose of ciprofloxacin (500mg) tablet of the reference (R) and three test (A, B, D) products in the fasting state in a balanced incomplete block design. Serial blood samples were collected after dosing at 8 different time intervals for a period of 24 hours. Serum obtained from blood was analysed for ciprofloxacin with microbiology assay while plasma samples were analysed using UV-Vis spectrophotometric analytical method at a wavelength of 272.4 nm. The pharmacokinetic parameters were determined using non-compactmental as implemented in WinNonlin pharmacokinetic program. The 90% confident interval of the log transformed mean values of the test/reference ratios for the pharmacokinetic parameters (C max ), (AUC 0-t ), ant the (AUC 0-∞ )were calculated and used to determine the bioequivalence acceptance range of 80 – 125%. Result: The pharmacokinetic parameters from the UV-Vis analytical method showed no statistically significant difference between the reference and the tested brands as the mean C max obtained for the reference sample (R) was the highest (275.50 (±3.86) µg/ml) occurring at a t max of 6.83 (±1.89) h, followed by B (222.17 (±2.11) µg/ml) at 5.08 (±0.98) h, C (202.00 (±0.55) µg/ml) at 3.63 (±1.02) h and A (192.00 (±1.10) µg/ml) at 7.00 (±1.11) h. The value obtained for the 90% CI for log-transformed ration for C max is A/R (94.7, 101.6), B/R (87.8, 101.6), C/R (91.2, 99.2) which is within the acceptable range of 80% to 125% as it is for AUC 0-t and AUC 0-∞ also. The obtained outcome for microbiological assay reflected similarities with the UV-Vis assay as the pharmacokinetic parameters are not different statistically and the value obtained for the 90% CI for log-transformed ration for C max, AUC 0-t and AUC 0-∞ are within the regulatory acceptable range. Conclusion: The four formulations were considered to be bioequivalent as the peak plasma concentration and AUC parameter analysis of variance reflected no significant difference between the innovator brand and the three other brands.