School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou 325035, China.
The Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325035, China.
J Pharm Biomed Anal. 2019 Feb 5;164:27-31. doi: 10.1016/j.jpba.2018.10.016. Epub 2018 Oct 9.
Kaurenoic acid (KA), a kaurane diterpene found in several medicinal plants, is an active ingredient with potential anti-inflammatory, anticonvulsant, antibacterial and antitumor activities. In this work, an ultra-performance liquid chromatography-tandem mass spectrometry method (UPLC-MS/MS) was firstly developed and validated to quantify kaurenoic acid in rat plasma. Rhein was chosen as the internal standard (IS) and the plasma was processed with one-step acetonitrile protein precipitation; the chromatographic separation was achieved on a HSS T3 (2.1 × 50 mm, 1.8 μm) column with the mobile phase consisting of acetonitrile and water containing 0.1% formic acid via gradient elution. An electrospray ionization source was applied and operated in the negative ion and multiple reaction monitoring (MRM) modes. Kaurenoic acid and IS were quantified using the transitions of m/z 301.2→301.2 (pseudo MRM) and m/z 283.2 → 238.9, respectively. The calibration curves were linear over the range of 5∼ 100 ng/mL (R = 0.990). The lower limit of quantification (LLOQ) was 5 ng/mL. The intra- and inter- day precision (RSD) ranged from 3.0% to 11.4%. The matrix effect and extraction recovery were within acceptable limits. The validated method was successfully applied to the pharmacokinetic study of kaurenoic acid in rats after oral administration at three dosages.
高乌头酸（KA）是一种在多种药用植物中发现的贝壳杉二萜，是一种具有潜在抗炎、抗惊厥、抗菌和抗肿瘤活性的有效成分。在这项工作中，首次建立并验证了一种超高效液相色谱-串联质谱法（UPLC-MS/MS）来定量大鼠血浆中的高乌头酸。瑞因被选为内标（IS），并用一步乙腈蛋白沉淀法处理血浆；色谱分离在 HSS T3（2.1×50mm，1.8μm）柱上进行，流动相由乙腈和含 0.1%甲酸的水组成，采用梯度洗脱。采用电喷雾电离源，在负离子和多重反应监测（MRM）模式下进行操作。高乌头酸和 IS 的定量采用 m/z 301.2→301.2（伪 MRM）和 m/z 283.2→238.9 的跃迁进行。校准曲线在 5∼100ng/mL 范围内呈线性（R=0.990）。定量下限（LLOQ）为 5ng/mL。日内和日间精密度（RSD）范围为 3.0%至 11.4%。基质效应和提取回收率在可接受范围内。该验证方法成功应用于大鼠口服三种剂量后高乌头酸的药代动力学研究。
