Study on relative bioavailability of mifepristone capsules by HPLC

OBJECTIVE To establish a reversed phase HPLC method for determination of mifepistone in plasma and to study the pharmacokinetics and relative bioavailability following oral administration of domestic mifepistone tablets and mifepistone capsules in healthy volunteers.METHODS Eighteen volunteers were randomly divided into 2 groups.Grope I first administrated the trial preparation mifepristone capsules,and then followed by the reference preparation mifepristone tablet,while group II received the reference preparation first,and followed by the trial preparation.The plasma concentration of mifepristone was measured by HPLC.ANOVA was used to check the difference of the means of the pharmacokinetic parameters between the two preparations.Bioequivalence was determined by two one-side t-tests.RESULTS After the volunteers of taking trial preparation or reference preparation 25 mg,the pharmacokinetic parameters,AUC_(0-48),t_(1/2),t_(max),C_(max)were((5 048.7)±(552.2))μg·h·L~(-1) and((5 085.8)±(544.5))μg·h·L~(-1),((44.6)±(13.5)) h and((40.7)±(9.3)) h,((1.03)±(0.27)) h and((0.94)±(0.16)) h,((461.6)±(38.5))μg·L~(-1) and((468.64)±(51.8))μg·L~(-1),respectively.The relative bioavailability was((99.8)±(10.5))%.No significant differences were found among the main pharmacokinetic parameters after ANOVA.CONCLUSION HPLC method for determination of mifepristone in human plasma is fast and reliable.The two preparations were bioequivalent.