Establishment of in vitro evaluation model for CYP2B6 induction and its application to screen inducers among TCMs / 药学学报

This paper is to report the development of a high-throughput in vitro system to screen hPXR/CAR mediated CYP2B6 drug inducers, and the application of it into the quick determination of induction activity toward CYP2B6 by various commonly used traditional Chinese medicines (TCMs) extract. Dual reporter gene assays were performed. The hPXR/CAR expression vectors and the reporter vector pGL3-CYP2B6-Luc involved in the distal and proximal promoters of CYP2B6 were co-transfected into HepG2 cells. Relative luciferase activities in cell lysate were analyzed after 48 h treatment of blank vehicle or drugs to determine the induction activity toward CYP2B6 by various commonly used TCMs extract. The positive hPXR/hCAR activators rifampicin and CITCO were applied to make sure that the reporter gene model was successfully established. Then 5 kinds of commonly used TCM extracts and 1 herbal compound were successfully investigated, some were found to activate hPXR or hCAR and therefore have the potential to induce CYP2B6 enzyme. This is the first domestic article to report the hCAR3-mediated CYP2B6 induction model and the establishment of a reporter gene system for hPXR/CAR-mediated CYP2B6 induction can be an effective and systemic in vitro method to investigate the drug inducers of CYP2B6 and to explain the mechanism involved.

Analysis of species-dependent hydrolysis and protein binding of esmolol enantiomers / 药物分析学报

The stereoselective hydrolysis of esmolol in whole blood and in its separated components from rat,rabbit and human was investigated.Blood esterase activities were variable in different species in the order of rat ＞ rabbit ＞ human.Rat plasma showed the high esterase activity and had no stereoselectivity to enantiomers.Rabbit red blood cell (RBC) membrane,RBC cytosol and plasma all hydrolyzed esmolol but with different esterase activity,whereas the hydrolysis in RBC membrane and cytosol showed significant stereoselectivity towards R-(+)-esmolol.Esterase in RBC cytosol from human blood mainly contributed to the esmolol hydrolysis,which was demonstrated with no stereoselctivity.Esterase in human plasma showed a low activity,but a remarkable stereoselectivity with R-(+)-esmolol.In addition,the protein concentration affected the hydrolysis behavior of esmolol in RBC suspension.Protein binding of esmolol enantiomers in human plasma,human serum albumin (HSA) and α1-acid glycoprotein (AGP) revealed that there was a significant difference in bound fractions between two enantiomers,especially for AGP.Our results indicated that the stereoselective protein binding might play a role in the different hydrolysis rates of esmolol enantiomers in human plasma.

Analysis of chiral non-steroidal anti-inflammatory drugs flurbiprofen, ketoprofen and etodolac binding with HSA / 药物分析学报

The protein binding of non-steroidal anti-inflammatory drugs flurbiprofen,ketoprofen and etodolac with human serum albumin (HSA) was investigated using indirect chiral high performance liquid chromatography (HPLC) and ultrafiltration techniques.S-(-)-2-(1-naphthyl)-ethylamine (S-NEA) was utilized as chiral derivatization reagent and pre-column derivatization RP-HPLC method was established for the separation and assay of the three pairs of enantiomer.The method had good linear relationship over the investigated concentration range without interference.The average extraction efficiency was higher than 85％ in different systems,and the intra-day and inter-day precisions were less than 15％.In serum albumin,the protein binding of etodolac enantiomers showed significant stereoselectivity that the affinity of S-enantiomer was stronger than R-enantiomer,and the stereoselectivity ratio reached 6.06; Flurbiprofen had only weak stereoselectivity in HSA,and ketoprofen had no stereoselectivity at all.Scatchard curves showed that all the three chiral drugs had two types of binding sites in HSA.

Analysis of chiral non-steroidal anti-inflammatory drugs flurbiprofen, ketoprofen and etodolac binding with HSA / 药物分析学报

The protein binding of non-steroidal anti-inflammatory drugs flurbiprofen, ketoprofen and etodolac with human serum albumin （HSA） was investigated using indirect chiral high performance liquid chromatography （HPLC） and ultrafiltration techniques. S-（-）-1-（1-naphthyl）- ethylamine （S-NEA） was utilized as chiral derivatization reagent and pre-column derivatization RP-HPLC method was established for the separation and assay of the three pairs of enantiomer. The method had good linear relationship over the investigated concentration range without interference. The average extraction efficiency was higher than 85% in different systems, and the intra-day and inter-day precisions were less than 15%. In serum albumin, the protein binding of etodolac enantiomers showed significant stereoselectivity that the affinity of S-enantiomer was stronger than R-enantiomer, and the stereoselectivity ratio reached 6.06; Flurbiprofen had only weak stereoselectivity in HSA, and ketoprofen had no stereoselectivity at all. Scatchard curves showed that all the three chiral drugs had two types of binding sites in HSA.