Pharmacokinetic behavior of 16-dehydropregnenolone after intramuscular administration in rats

The pharmacokinetics of 16-dehydropregnenolone (16-DHP),a sterols compound isolated from Solanum lyratum Thunb.,was investigated in rats following a single intramuscular administration (40 mg/kg).The concentration of 16-DHP in rat plasma was determined by a high performance liquid chromatography (HPLC) method with UV detection.Levonorgestrel was used as the internal standard (IS).The pharmacokinetic parameters of 16-DHP were derived by non-compartmental method.After a single intramuscular administration,the maximum plasma concentration (Cmax,) was (289 ±25)ng/mL,time to reach Cmax(tmax) was (0.38±0.14) h,the elimination half-life (t1/2) was (2.5±1.1)h,the area under the plasma concentration-time curve from time zero to the time of the last measurable concentration (AUC10-t)) was (544 ± 73 )ng· h/mL.The results indicated that 16-DHP was alsorbed quickly and eliminated rapidly in rats after the intramuscular injection.