Abstract:
Objective To investigate the bioavailability and pharmacokinetics of silybin A and silybin B in rats, respectively. Methods Following iv and ig administration of silybin to 20 Wistar rats, the plasma samples were collected at different time points up to 12 h. Sample pretreatment was involved in one-step protein precipitation with acetonitrile. Silybin A and silybin B were simultaneously determined by LC-MS/MS. Results After ig dosing silybin 28, 56, and 112 mg/kg to rats, the t1/2β values were 5.48, 5.08, and 5.73 h for silybin A, and 4.56, 4.12, and 5.53 h for silybin B; The Cmax were 674.3, 1349.4, and 2042.5 ng/mL for silybin A, and 671.0, 1365.4, and 2066.2 ng/mL for silybin B; The Tmax were 0.20, 0.23, and 0.20 h for silybin A, and 0.20, 0.23, and 0.20 h for silybin B; The AUC were 454.4, 845.9, and 1219.5 h?ng/mL for silybin A, and 432.0, 817.1, and 1153.6 h?ng/mL for silybin B. The absolute bioavailabilities of silybin A and silybin B were 2.86% and 1.93%, respectively. Conclusion Silybin A and silybin B have very low bioavailability after ig administration, and there is no significant difference in the pharmacokinetic parameters between silybin A and silybin B, which indicates that the two diastereoisomers have similar pharmacokinetic behavior in rats.