Gao Song, Zhao Jing, Yin Taijun, Ma Yong, Xu Beibei, Moore Anthony N, Dash Pramod K, Hu Ming
Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, The University of Houston, 1441 Moursund Street, Houston, TX 77030, USA.
Department of Neurobiology & Anatomy, The University of Texas Health Science Center at Houston, P.O. Box 20708, Houston, TX 77225, USA.
J Chromatogr B Analyt Technol Biomed Life Sci. 2015 Apr 1;986-987:54-9. doi: 10.1016/j.jchromb.2015.01.034. Epub 2015 Feb 7.
The purpose of this study is to develop and validate an UPLC-MS/MS method to quantify ethoxzolamide in plasma (EZ) and apply the method to absorption, brain distribution, as well as pharmacokinetic studies. A C₁₈ column was used with 0.1% of formic acid in acetonitrile and 0.1% of formic acid in water as the mobile phases to resolve EZ. The mass analysis was performed in a triple quadrupole mass spectrometer using multiple reaction monitoring (MRM) with positive scan mode. The results show that the linear range of EZ is 4.88-10,000.00 nM. The intra-day variance is less than 12.43% and the accuracy is between 88.88 and 108.00%. The inter-day variance is less than 12.87% and accuracy is between 89.27 and 115.89%. Protein precipitation was performed using methanol to extract EZ from plasma and brain tissues. Only 40 μL of plasma is needed for analysis due to the high sensitivity of this method, which could be completed in less than three minutes. This method was used to study the pharmacokinetics of EZ in SD rats, and the transport of EZ in Caco-2 and MDCK-MDR1 overexpressing cell culture models. Our data show that EZ is not a substrate for p-glycoprotein (P-gp) and its entry into the brain may not limited by the blood-brain barrier.
本研究的目的是开发并验证一种超高效液相色谱-串联质谱法（UPLC-MS/MS）来定量测定血浆中的乙氧唑胺（EZ），并将该方法应用于吸收、脑分布以及药代动力学研究。使用C₁₈柱，以乙腈中0.1%的甲酸和水中0.1%的甲酸作为流动相来分离EZ。在三重四极杆质谱仪中采用多反应监测（MRM）和正离子扫描模式进行质谱分析。结果表明，EZ的线性范围为4.88 - 10,000.00 nM。日内变异小于12.43%，准确度在88.88%至108.00%之间。日间变异小于12.87%，准确度在89.27%至115.89%之间。采用甲醇进行蛋白沉淀以从血浆和脑组织中提取EZ。由于该方法灵敏度高，分析仅需40 μL血浆，且可在不到三分钟内完成。该方法用于研究SD大鼠中EZ的药代动力学，以及EZ在过表达Caco-2和MDCK-MDR1细胞培养模型中的转运。我们的数据表明，EZ不是P-糖蛋白（P-gp）的底物，其进入脑内可能不受血脑屏障的限制。
