HPLC assay of levofloxacin in human plasma and its relative bioavailability

Aim To use the HPLC assay for determination of levofloxacin in human plasma and to investigate the pharmacokinetics and bioequivalence of levofloxacin.Methods The improved RP-HPLC assay was performed to determine different timespot in 20 healthy volunteers.In the study periods,a single 500 mg dose of each tablet was administered to each volunteer.The main pharmacokinetics parameter and relative bioavailability were calculated,and the bioequivalence were estimated.Results There were similar pharmacokinetics parameter between the reference and the test tablet,and the main pharmacokinetics parameter were as follows:AUC_(0～t)(R)(6.77±1.74)mg·L~(-1)·h~(-1)、AUC_(0～t)(T)(7.26±1.34)mg·L~(-1)·h~(-1),AUC_(0～∞)(R)(8.58±1.72)mg·L~(-1)·h~(-1)、AUC_(0～∞)(T)(8.96±1.27)mg·L~(-1)·h~(-1),C_(max)(R)(0.99±0.16)mg·L~(-1)、C_(max)(T)(0.98±0.18)mg·L~(-1),T_(max)(R)(0.93±0.23)h,T_(max)(T)(0.96±0.26)h,T_(1/2α)(R)(9.71±3.31)h,T_(1/2α)(T)(11.15±3.55)h.The relative bioavailability of the test tablet was(110.66±37.14)%;(113.05±38.89)% for the reference tablet.Either was between the range of 81%～126%,and in accordance with the requirementment of relative bioavailability.The results of bioequivalence showed that there was no significant difference between the reference and test formulations in the AUC and C_(max).Conclusion The reference and test formulations are bioequivalent.