Sripalakit Pattana, Nermhom Penporn, Saraphanchotiwitthaya Aurasorn
Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand.
Biomed Chromatogr. 2006 Aug;20(8):729-35. doi: 10.1002/bmc.588.
A simple high-performance liquid chromatographic method for the determination of doxazosin in human plasma was developed and validated. Prazosin was used as internal standard. After extraction twice with ethyl acetate, chromatographic separation of doxazosin in human plasma was carried out using a reversed-phase Apollo C18 column (250 x 4.6 mm, 5 microm) with mobile phase of methanol-acetonitrile-0.04 m disodium hydrogen orthophosphate (22:22:56, v/v/v) adjusted to pH 4.9 with 0.9 m phosphoric acid and quantified by fluorescence detection operated with an excitation wavelength of 246 nm and an emission wavelength of 389 nm. The lower limit of quantification (LLOQ) of this assay was 1 ng/mL using 500 microL human plasma. Linearity was established over the range 1-25 ng/mL (r2 > 0.9994). The intra- and inter-day accuracy ranged from 90.5 to 104.4% and the coefficient of variation were not more than 8.6% for both intra- and inter-day precision, over the range of the calibration curve. The absolute recoveries of doxazosin and prazosin from human plasma were more than 91%. Doxazosin demonstrated acceptable short-term, long-term and freeze-thaw stability in human plasma. The assay has been successfully applied to plasma sample ana-lysis for pharmacokinetic study.
建立并验证了一种简单的高效液相色谱法用于测定人血浆中的多沙唑嗪。以哌唑嗪作为内标。用乙酸乙酯萃取两次后，采用反相Apollo C18柱（250×4.6 mm，5μm）对人血浆中的多沙唑嗪进行色谱分离，流动相为甲醇 - 乙腈 - 0.04 m磷酸氢二钠（22:22:56，v/v/v），用0.9 m磷酸调节pH至4.9，通过荧光检测进行定量，激发波长为246 nm，发射波长为389 nm。该方法使用500μL人血浆时的定量下限（LLOQ）为1 ng/mL。在1 - 25 ng/mL范围内建立了线性关系（r2＞0.9994）。在校准曲线范围内，日内和日间准确度在90.5%至104.4%之间，日内和日间精密度的变异系数均不超过8.6%。多沙唑嗪和哌唑嗪从人血浆中的绝对回收率均超过91%。多沙唑嗪在人血浆中表现出可接受的短期、长期和冻融稳定性。该方法已成功应用于药代动力学研究的血浆样本分析。
