Comparative bioavailability of two moxifloxacin tablet products after single dose administration under fasting conditions in a balanced, randomized and cross-over study in healthy volunteers

Moxifloxacin, a 4th generation of fluoroquinolones, is a broad spectrum antibacterial agent against respiratory tract pathogens, including Gram-positive and Gram-negative bacteria, anaerobic bacteria and atypical respiratory tract pathogens. In order to evaluate the efficacy and safety of generic moxifloxacin products, the bioequivalence of these generic products with an approved reference formulation should be demonstrated. Thus, the aim of this study was to compare the rate and extent of absorption of a new generic film coated moxifloxacin tablet product (Rapiflox (R), Atlantic Laboratories Corporation Ltd., Bangkok, Thailand) with that of a reference product (Avelox (R), Bayer Health Care AG, Leverkusen, Germany) when given as a single dose. A crossover study was performed in 20 healthy Thai volunteers. The subjects received either a 400 mg tablet of the reference or test product after overnight fasting. Blood samples were collected at pre-dose (0 hour) and at 0.25, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 24 and 34 hours post-dose. Moxifloxacin plasma level was measured by a validated HPLC method with fluorescence detector. Fharmacokinetic parameters were calculated using a non-compartmental model. The geometric mean of maximum concentration (C-max) of the test product was 4,069.64 ng/ml, with median time to achieve maximum concentration (t(max)) at 2 hours (range 0.25 - 6.00 hours), while the geometric mean C-max and median tmax of the reference product was 4,211.98 ng/ml and 2.00 hours (range 0.25 - 8.00 hours). Furthermore, the geometric means of AUC(0-tlast) and AUC(0-infinity) for the test product were 49,731.66 and 51,865.89 ngxh/ml while those of the reference product were 51,927.97 and 54,455.93 ngxh/ml. The geometric mean of the ratios of Test/Reference for the log-transformed Cm, AUC(0-tlast) and AUC(0-infinity) of moxifloxacin and their 90% CIs were 96.62% (83.21 - 112.19%), 95.77% (87.07-105.34%) and 95.24 (86.52 - 104.85%), respectively. Therefore, it can be concluded that these two moxifloxacin tablet products were bioequivalent in healthy Thai volunteers under fasting condition.