Development of a high sensitivity UHPLC-MS/MS method to determine the twelve compounds of Physochlainae Radix extract and application to a pharmacokinetic study in rats

Physochlainae Radix (PR) is generally applied for treating cough and asthma. In this study, a sensitive ultra-highperformance liquid chromatography coupled with triple quadrupole mass spectrometry (UHPLC-MS/MS) method was established and validated for the simultaneous determination of twelve components (scopolamine, anisodamine, hyoscyamine, protocatechuic acid, fabiatrin, scopolin, 4-hydroxybenzoic acid, caffeic acid, tropic acid, scopoletin, isoquercitrin, and scoparone) of PR extract in rat plasma. ACQUITY UPLC CSH C18 column was employed for the chromatographic separation with the mobile phase system consisting of acetonitrile and 0.1 % (v/v) formic acid aqueous solution. The intra-day and inter-day precisions of twelve analytes was less than 9.33 %, and the accuracy ranged from -11.08 to 11.89 %. The extraction recoveries of the analytes ranged from 76.42 to 93.17 % and the matrix effects varied from 76.02 to 90.56 %. The results of stability tests demonstrated that the analytes were stable under the different conditions and their relative standard deviation were less than 13.06 %. The developed method was firstly successfully applied to the pharmacokinetic study of the twelve analytes of PR extract in rats, and the pharmacokinetic results showed that the maximum concentration (Cmax, 1553.51 +/- 736.52 ng/mL) of tropic acid were relatively large, which was related to the fact that scopolamine and anisodamine were metabolized to tropic acid in vivo. The elimination half-life (T1/2) of fabiatrin, scopolin, 4-hydroxybenzoic acid, and tropic acid were 6.45, 6.16, 9.87, and 7.12 h, suggesting that these analytes were kept for a longer duration in vivo. This research would provide meaningful reference for PR in clinical use.