Determination of the progesterone antagonist lilopristone in serum by RP-HPLC
Yu, C.; Zhang, H.; Hong, Y.C.; Bao, C.Y.; Wu, Z.Y.; Ding, X.C.
Yao Xue Xue Bao 30(6): 449-453
1995
ISSN/ISBN: 0513-4870 PMID: 7572183 Document Number: 451805
To 1.0 ml of serum containing lilopristone were added RU-486 solution (internal standard, IS) and 1 ml of 1.0 mol cntdot L-1 NaOH. The mixture was extracted with diethyl ether for 2 times. After extraction, the combined organic phase was evaporated to dryness and the residue was dissolved in the mobile phase and washed with petroleum ether. After centrifugation, 20 mu-l of the lower layer was subjected to HPLC. A mu-Bondapak-C-18 (10 mu-m) column (30 cm times 3.9 mm) was used and the column temperature was kept at 50 degree C. The flow rate of mobile phase (methanol-dichloromethane-0.01 mol cntdot L-1 phosphate buffer, pH 4.0, 67:5:28 v/v) was 1.1 ml cntdot min-1 and UV detection was performed at 302 nm. The retention times of lilopristone and IS were 6.85 and 9.07 min respectively and the detection limit was 10 ng cntdot ml-1 (S/N gtoreq 4) serum. The extraction recoveries of lilopristone and IS were over 85%. The relative standard deviations were 2.21 to 4.23%. This method has been applied to study the pharmacokinetic of lilopristone in rats.