AIM: To determine the low content of Ophiopogon japonicus saponin metabolite in vivo. METHODS: HPLC-MS method of determining rat's metabolite diosgenin in vivo was established after single-dose oral Ophiopogon japonicus saponin enteric microsphere. RESULTS: The detection limit was about 50 ng/mL,Linearity,precision of intra and inter-day and reproducibility of the method were good. CONCLUSION: This method accords with the analysis requirement.It can give an effective measure and foundation for studying TCM saponin bioavailability.

Objective To study the relative bioavailability after ig rats with Ophiopogon japonicus saponin enteric microsphere in single-dose so as to give directly preparation quality evaluation. Methods(Establishing the) analysis method of HPLC-MS and dealing with the blood sample by solid phase extraction. Determining the diosgenin concentration in plasma after ig Ophiopogon japonicas saponin enteric microsphere and the suspension as comparison in single-dose, and calculating pharmacokinetic parameters and relative bioavailability. Results C_(max), t_(max), and AUC_(0-72) were (637.81?17.23) ng/mL, (4.0?0.0) h, and 7 840.01?412.03, respectively. Conclusion The characteristics of absorption, distribution, and elimination are resembled in rats between two preparations by ig in single-dose. The pharmacokinetic parameters are also identical. The relative bioavailability is (91.10?3.44)%.