The aim of this study is to establish an HPLC method for simultaneous determinations of mifepristone and its metabolites, mono-demethylated mifepristone, di-demethylated mifepristone and C-hydroxylated mifepristone in plasma and to evaluate the pharmacokinetic characteristics of mifepristone tablet. Twenty healthy female Chinese subjects were recruited and a series of blood samples were collected before and after 0.25, 0.5, 1.0, 1.5, 2.0, 4.0, 8.0, 12.0, 24.0, 48.0, 72.0 and 96.0 hours administration by a single oral dose of 75 mg mifepristone tablet. Mifepristone and its three metabolites were extracted from plasma using ethyl acetate and determined by high performance liquid chromatography. The main pharmacokinetic parameters of mifepristone and its metabolites, including Cmax, tmax, MRT, t(1/2), V, CL, AUC(0-96 h) and AUC(0-infinity), were calculated by Drug and Statistical Software Version 2.0. The simple, accurate and stable method allows the sensitive determinations ofmifepristone and its metabolites in human plasma up to 4 days after oral administration of 75 mg mifepristone tablet and the clinical applications of their pharmacokinetic studies.

ObjectiveTo investigate the effect of icariin （ICA） on steroid-induced ferroptosis in bone microvascular endothelial cells （BMECs）. MethodsRat BMECs were selected and treated with 500 mg·L^-1 hydrocortisone for 1.5 h to establish a ferroptosis model of BMECs. The experimental cells were divided into a blank group， hormone group （500 mg·L^-1 hydrocortisone）， ICA group （500 mg·L^-1 hydrocortisone + 34 mg·L^-1 ICA）， and ferroptosis agonist group （500 mg·L^-1 hydrocortisone + 34 mg·L^-1 ICA + 2.7 mg·L^-1 erastin）. Cell viability was detected by CCK-8. The levels of ferrous ion， glutathione （GSH）， malondialdehyde （MDA）， superoxide dismutase （SOD）， and reactive oxygen species （ROS） were detected by related kit species. The ferroptosis-related proteins， such as glutathione peroxidase 4（GPX4）， ferritin light chain （FTL）， and transferrin receptor protein1 （sTfR） were detected by Western blot， as well as autophagy-related proteins including microtubule-associated protein 1 light chain 3B （LC3B）， Beclin1， B-cell lymphoma-2 （Bcl-2）， and Caspase-3. Results500 mg·L^-1 hydrocortisone intervention for 1.5 h could effectively induce ferroptosis in BMECs， and ferroptosis levels could reach a peak as the intervention continued. In terms of cellular antioxidant capacity， compared with those in the blank group， the cell vitality， GSH in the hormone group decreased significantly， and the levels of ROS， SOD， MDA， and ferrous ions were significantly increased （P<0.01）. Compared with those in the hormone group， the cell viability， GSH were significantly increased， and the levels of ROS， SOD， MDA， and ferrous ions were decreased in the ICA group （P<0.01）. Compared with those in the ICA group， the cell vitality， GSH in the ferroptosis agonist group decreased significantly， and the levels of ROS， SOD， MDA， and ferrous ions increased significantly （P<0.01）. In terms of the relationship between ferroptosis and autophagy， compared with the blank group， the hormone group had significantly increased expression levels of LC3B， sTfR， Beclin1， and FTL and significantly decreased expression levels of GPX4 （P<0.01）. Compared with the hormone group， The ICA group had significantly decreased expression levels of LC3B， sTfR， and FTL and significantly increased expression levels of Beclin 1 and GPX4 （P<0.01）. Compared with those in the ICA group， the expression levels of LC3B， sTfR， and FTL increased in the rapamycin group， and those of Beclin 1 and GPX4 decreased （P<0.01）. In terms of cell ferroptosis and apoptosis，compared with the blank group， the hormone group had significantly increased expression levels of FTL， sTfR and Caspase-3 and significantly decreased expression levels of GPX4， and Bcl-2 （P<0.01）. Compared with the hormone group， the ICA group had significantly decreased expression levels of FTL， sTfR and Caspase-3 and significantly increased expression levels of GPX4， and Bcl-2 （P<0.01）. Compared with those in the ICA group， the expression levels of FTL， sTfR and Caspase-3 in the ferroptosis agonist group were increased， and the expression levels of GPX4， and Bcl-2 were decreased （P<0.01）. In terms of cell function，compared with that in the blank group， the ability of cell migration and tube formation was significantly decreased in the hormone group （P<0.01）. Compared with that in the hormone group， the cell migration and tube formation ability in the ICA group were significantly increased （P<0.01）. ConclusionFerroptosis is involved in steroid-induced damage in BMECs. ICA can inhibit steroid-induced ferroptosis in BMECs， and the mechanism may be associated with the inhibition of ferroptosis by regulating autophagy.