title: LC-MS determination and pharmacokinetic studies of ursolic acid in rat plasma after administration of the traditional chinese medicinal preparation Lu-Ying extract.
abstract: Sambucus chinensis L. is a native perennial herb distributed throughout China. In traditional Chinese medicine (TCM), this herb is known as Lu-Ying. Ursolic acid is the major effective constituent of Lu-Ying. A rapid, sensitive, and accurate liquid chromatography-mass spectrometry (LC-MS) method for the determination of ursolic acid in rat plasma was developed and validated. Plasma samples taken from rats that had received Lu-Ying extract orally were acidified with acetic acid and then extracted with a mixture of hexane-dichloromethane-2-propanol (20:10:1, v/v/v). Separation of ursolic acid was accomplished on a C(18) column interfaced with a single quadrupole mass spectrometer. The mobile phase consisting of methanol and water (95:5, v/v) was delivered at a flow rate of 1.0 ml/min. Atmospheric pressure chemical ionization was operated in negative-ion mode. Using selected ion-monitoring mode, the deprotonated molecules [M-H](-) at m/z 455 and 469 were used to quantify ursolic acid and glycyrrhetic acid (internal standard), respectively. The assay was shown to be linear over the range of 10-1000 ng/ml (r> or =0.9960) with a lower limit of quantification of 10 ng/ml. The method was shown to be reproducible and reliable with intraday precision below 7.8%, interday precision below 8.1%, accuracy within +/-4.3%, and mean extraction recovery excess of 83.6%, which were all calculated from the blank plasma sample spiked with ursolic acid at three concentrations of 20, 200, and 800 ng/ml. The LC-MS method has been successfully applied to pharmacokinetic studies of ursolic acid after oral administration of Lu-Ying ethanolic extract (at a dose containing 80.32 mg/kg ursolic acid) to rats. The main pharmacokinetic parameters were: t(1/2), 4.3 h; K(e), 0.16 1/h; t(max), 1.0 h; C(max), 294.8 ng/ml; AUC(0-t) and AUC(0-infinity), 1007.1 ng.h/ml and 1175.3 ng.h/ml, respectively.
authors.affiliation: School of Pharmacy, Shenyang Pharmaceutical University, Liaoning Province, P. R. China.
authors.forename: Qiongfeng
authors.initials: Q
authors.lastname: Liao
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Ying
authors.initials: Y
authors.lastname: Jia
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Chen
authors.forename: Qiutao
authors.initials: Q
authors.lastname: Gao
authors.forename: Kaishun
authors.initials: K
authors.lastname: Bi
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity; D014315:Triterpenes / Q000097:blood*; D000097245:Ursolic Acid
chemical_list: D004365:Drugs, Chinese Herbal; D014315:Triterpenes; D000097245:Ursolic Acid