Gaspar Julio R, Qu Jun, Straubinger Ninfa L, Straubinger Robert M
The Department of Pharmaceutical Sciences, University at Buffalo, State University of New York, Amherst, NY 14260-1200, USA.
Analyst. 2008 Dec;133(12):1742-8. doi: 10.1039/b806856a. Epub 2008 Oct 3.
The taxanes are among the most important cancer chemotherapy drugs approved for clinical use in the last two decades. Paclitaxel is used as first-line therapy for a variety of cancers, and numerous drug delivery approaches are under investigation to enhance its selectivity and effectiveness against tumors. One strategy is to produce sustained, low drug levels within the tumor to enhance apoptosis and inhibit angiogenesis. The interest in altering drug concentration/time exposure profiles to improve therapeutic outcomes creates the necessity to quantify low concentrations of paclitaxel in cells or tissues. Here, a selective solid phase extraction (SPE) method, coupled with a capillary liquid chromatography-tandem mass spectrometry (microLC-MS/MS) method, was developed to quantify low, therapeutically relevant concentrations of paclitaxel that could not be analyzed using conventional LC-MS/MS. Under optimized SPE wash and elution conditions, paclitaxel was selectively extracted from biological samples, and most matrix components were removed. A 150 x 0.5 mm ID ODS capillary column was used for microLC separation and the flow rate was 12 microL min(-1). Sample extracts were focused at the front of the microLC column and then eluted with a gradient. The lower limits of detection and quantification were 5 and 20 pg mL(-1), respectively, permitting quantification of paclitaxel in small tissue samples or in cultured cells exposed to low drug concentrations. The quantitative linear range was 20-20 000 pg mL(-1). The ability to quantify these low concentrations of paclitaxel provides an important tool to study the concentration-dependent pharmacological effects of this important drug.
紫杉烷类是过去二十年来被批准用于临床的最重要的癌症化疗药物之一。紫杉醇被用作多种癌症的一线治疗药物，目前正在研究多种药物递送方法以提高其对肿瘤的选择性和有效性。一种策略是在肿瘤内产生持续的低药物水平，以增强细胞凋亡并抑制血管生成。改变药物浓度/时间暴露曲线以改善治疗效果的研究兴趣使得有必要对细胞或组织中的低浓度紫杉醇进行定量。在此，开发了一种选择性固相萃取（SPE）方法，结合毛细管液相色谱-串联质谱（microLC-MS/MS）方法，以定量无法使用传统LC-MS/MS分析的低治疗相关浓度的紫杉醇。在优化的SPE洗涤和洗脱条件下，从生物样品中选择性提取紫杉醇，并去除大部分基质成分。使用150×0.5 mm内径的ODS毛细管柱进行microLC分离，流速为12 μL min(-1)。样品提取物在microLC柱前端聚焦，然后用梯度洗脱。检测限和定量限分别为5和20 pg mL(-1)，能够对小组织样品或暴露于低药物浓度的培养细胞中的紫杉醇进行定量。定量线性范围为20-20 000 pg mL(-1)。定量这些低浓度紫杉醇的能力为研究这种重要药物的浓度依赖性药理作用提供了重要工具。
