The aim of this study was to establish a correlation between in vitro dissolution and in vivo absorption data of prepared immediate release Gemifloxacin tablets (Zagam) and compare with conventional tablets of Gemifloxacin (Factive). In vitro release data were obtained for test and reference tablets by using the USP apparatus II, 0.01N HCl of pH 2.0 at 50 rpm. A group of six healthy, male human subjects participated for in vivo study. Serial blood samples were collected at 0, 1, 2, 3, 4, 6, 8, 10, 12 and 24 hr. Gemifloxacin was measured by Ultra performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to establish in vitro-in vivo correlation while absorption profiles were derived using Wagner-Nelson equation. f2 and f1 were determined for the time intervals of 5, 10, 15, 20, 25, 30, 45 and 60 minutes and the obtained values were 97.97, 99.94, 95.87, 91.02, 99.05, 96.97, 86.80 and 100.00% for f2 and 11.5, 9.4, 14.0, 12.5, 10.6, 0.5, 0.2 and 0.9% for f1 at respective time intervals. The bioavailability of Gemifloxacin IR tablet containing 320 mg of Gemifloxacin mesylate and reference tablet was measured using pharmacokinetic parameters Cmax, Tmax, t1/2 and AUC. Moreover, the value of correlation coefficients for % in vivo absorption versus % in vitro dissolution of the two products were calculated to be 0.9443 and 0.9208.
