Zhu Jing, Zhou Xin, Zheng Hu, Li Zhangwan
School of Pharmacy, Sichuan University, Chengdu 610041, China.
J Chromatogr B Analyt Technol Biomed Life Sci. 2006 Aug 18;840(2):124-31. doi: 10.1016/j.jchromb.2006.04.041. Epub 2006 May 26.
An analytical method was developed for the determination of enantiomers of dencichine in plasma. Sample extraction from plasma was achieved by a solid-phase extraction (SPE) procedure using a C(18) cartridge, with carbocisteine as the internal standard. Plasma was deproteinized using inorganic acid and derivatizated before the SPE. Chiral separation of dencichine enantiomers was achieved by pre-column derivatization using o-phthaldialdehyde (OPA) and the chiral thiol N-isobutanoyl-L-cysteine (NIBC) to form diastereoisomeric isoindole derivatives that were separable by ODS column using a gradient solvent programme. The column eluent was monitored using mass spectrometry (MS). The conditions of MS detection were optimized, and selected ion monitoring was used to selectively detect D-dencichine and its arrangement isomer. High sensitivity and selectivity were obtained using this method. The limit of detection was determined to be 10 ng/ml for D-dencichine and 8 ng/ml for L-dencichine in plasma. The linearity was demonstrated over a wide range of concentrations, from 0.5 to 50 microg/ml for both enatiomers. The intra- and inter-day precision (C.V.), studied at four concentrations, was less than 7.0%. No interferences from endogenous amino acids and isomers of dencichine were found. The method was suitable for pharmacokinetic studies of dencichine enantiomers.
建立了一种测定血浆中灯盏花乙素对映体的分析方法。采用C(18)柱固相萃取(SPE)法从血浆中提取样品，以羧甲司坦为内标。血浆先用无机酸进行蛋白沉淀，然后在SPE前进行衍生化。灯盏花乙素对映体的手性分离通过使用邻苯二甲醛(OPA)和手性硫醇N-异丁酰-L-半胱氨酸(NIBC)进行柱前衍生化来实现，形成非对映异构的异吲哚衍生物，并通过ODS柱在梯度溶剂程序下进行分离。柱洗脱液采用质谱(MS)监测。对MS检测条件进行了优化，并采用选择离子监测选择性地检测D-灯盏花乙素及其排列异构体。该方法具有高灵敏度和高选择性。血浆中D-灯盏花乙素的检测限为10 ng/ml，L-灯盏花乙素的检测限为8 ng/ml。两种对映体在0.5至50 μg/ml的宽浓度范围内均表现出线性关系。在四个浓度水平下研究日内和日间精密度(C.V.)均小于7.0%。未发现内源性氨基酸和灯盏花乙素异构体的干扰。该方法适用于灯盏花乙素对映体的药代动力学研究。
