Department of Pharmaceutical Analysis and Analytical Chemistry, College of Pharmacy, Harbin Medical University, No. 157 Baojian Road, Nangang District, Harbin 150081, Heilongjiang, China.
Key Laboratory of Chinese Materia Medica (Ministry of Education), Heilongjiang University of Chinese Medicine, Harbin 150040, Heilongjiang, China.
J Pharm Biomed Anal. 2022 Sep 5;218:114858. doi: 10.1016/j.jpba.2022.114858. Epub 2022 Jun 2.
Uncaria rhynchophylla (Miq.) Miq. ex Havil (U. rhynchophylla), a traditional Chinese medicine that has been officially included in the Chinese Pharmacopeia, is used to treat cardiovascular and central nervous system diseases. The major alkaloids isolated from U. rhynchophylla are two pairs of epimer including rhynchophylline (RIN) and isorhynchophylline (IRN), along with corynoxeine (CN) and isocorynoxeine (ICN). An ultra-performance liquid chromatography with tandem mass spectrometry method (UHPLC-MS/MS), which was highly accurate, stable and sensitive, was established and validated for the simultaneous determination of four alkaloid compounds (RIN, IRN, CN, ICN) in rat plasma samples after oral administration of RIN, IRN, CN, ICN and U. rhynchophylla extract. In this study, the biotransformation and pharmacokinetics of RIN, IRN, CN and ICN were determined for the first time. An ACQUITY UPLC®HSS T3 column (1.8 µm, 2.1 mm × 100 mm) was used to complete the chromatographic separation within 3 min. The isocratic mobile phase was composed of 0.1 % formic acid water (v/v) and acetonitrile, and the flow rate was 0.2 mL/min. The multireaction monitoring mode was adopted, and the tandem mass spectrometry in the positive ion mode was detected by the electrospray ionization source. The method was fully verified and linear at a wide concentration (r > 0.9913), and the linear concentration range was 0.1552-124.5 ng/mL. The intraday and interday precisions of the four analytes were lower than 8.20 % and 13.42 %, respectively. The accuracy range was - 2.64 % and 13.63 %. The extraction recoveries of the analytes exceeded 83.74 %, and the matrix effect range was 98.43-103.7 % in the plasma samples. The four alkaloids can be quickly absorbed into the blood (T, 0.22-3.83 h) and cleared comparatively slowly (T, 7.67-12.13 h). This method has been successfully applied to the biotransformation and pharmacokinetic studies of SD rat plasma after oral administration of U. rhynchophylla extracts. This proved that RIN with IRN and CN with ICN can transform into each other in vivo. The results are of great significance for determining the mechanism of action and guiding the clinical application of U. rhynchophylla extracts.
钩藤（Miq.）Miq. ex Havil（U. rhynchophylla），一种已被正式列入中国药典的中药，用于治疗心血管和中枢神经系统疾病。从钩藤中分离得到的主要生物碱有两对差向异构体，包括钩藤碱（RIN）和异钩藤碱（IRN），以及柯诺辛（CN）和异柯诺辛（ICN）。建立并验证了一种超高效液相色谱-串联质谱法（UHPLC-MS/MS），该方法准确、稳定、灵敏，可用于同时测定大鼠口服 RIN、IRN、CN、ICN 及钩藤提取物后血浆中四种生物碱（RIN、IRN、CN、ICN）的浓度。在本研究中，首次确定了 RIN、IRN、CN 和 ICN 的生物转化和药代动力学。采用 ACQUITY UPLC®HSS T3 柱（1.8μm，2.1mm×100mm），在 3min 内完成色谱分离。等度流动相由 0.1%甲酸水（v/v）和乙腈组成，流速为 0.2mL/min。采用多反应监测模式，电喷雾源正离子模式检测串联质谱。该方法经过充分验证，具有较宽的浓度范围（r>0.9913），线性浓度范围为 0.1552-124.5ng/mL。四种分析物的日内和日间精密度均低于 8.20%，准确度范围为-2.64%和 13.63%。分析物的提取回收率均超过 83.74%，在血浆样品中基质效应范围为 98.43-103.7%。四种生物碱能迅速被血液吸收（T，0.22-3.83h），清除速度较慢（T，7.67-12.13h）。该方法已成功应用于 SD 大鼠口服钩藤提取物后血浆的生物转化和药代动力学研究。这证明了体内 RIN 与 IRN、CN 与 ICN 可以相互转化。研究结果对于确定钩藤提取物的作用机制和指导临床应用具有重要意义。
