Pharmacokinetics and Bioequivalence Study of Levonorgestrel Dispersible Tablets in Healthy Volunteers

OBJECTIVE To study the pharmacokinetics and bioequivalence of levonorgestrel dispersible tablets in healthy Chinese volunteers. METHODS A single oral dose 1.5 mg of levonorgestrel test and reference formulation were given to 20 healthy female volunteers in a randomized crossover study. The concentrations of levonorgestrel in plasma were determined by LC/MS/MS methods. The pharmacokinetic parameters and the relative bioequivalence of the two preparations of levonorgestrel were calculated by DAS Ver2.0 software. RESULTS The main pharmacokinetic parameters of levonorgestrel were as follows: Cmax were (29.28(6.15)ng·mL-1 and (30.63(6.44)ng·mL-1；Tmax were (1.71(0.24)h and (1.75(0.23)h；t1/2 were (17.56(6.07)h and (17.77(6.22)h；CL/F were (5.00(1.99)L·h-1 and (4.76(1.83)L·h-1；AUC0-t were (316.56(94.25)ng·h·mL-1 and (334.32(109.64) ng·h·mL-1；AUC0-t were (332.53(93.58)ng·h·mL-1 and (351.35(108.11)ng·h·mL-1 for test formulation and reference formulation respectively；The 90% confidence interval of AUC0-t, AUC0-∞ and Cmax of test formulation were 89.1%-102.1%, 89.0%-101.5% and 91.8%-100.0% respectively. The relative bioavailability of levonorgestrel dispersible tablets was (96.85(18.23)%. CONCLUSION The results of the statistic analysis showed that levonorgestrel test formulation and reference formulation were bioequivalent.