DePuy M E, Musson D G, Yu S, Fisher A L
Department of Drug Metabolism, Merck Research Laboratories, WP75A-303, 19486, West Point, PA, USA.
J Pharm Biomed Anal. 2002 Nov 7;30(4):1157-71. doi: 10.1016/s0731-7085(02)00451-x.
To support clinical pharmacokinetic studies in cancer patients, sensitive and specific methods for measuring 4-[1-(4-cyanobenzyl)-5-imidazolylmethyl]-1-(3-chlorophenyl) piperazinone (I), a farnesyl transferase inhibitor (FTI), in human plasma and urine were developed and validated. The methods are based on high-performance liquid chromatography (HPLC) with atmospheric pressure chemical ionization (APCI) and tandem mass spectrometric (MS/MS) detection in the positive ion mode using a heated nebulizer interface. Drug and internal standard were isolated from plasma or basified urine using automated solid-phase extraction on cyano cartridges. The organic extracts were dried, reconstituted in aqueous acetonitrile and injected into the system. Chromatographic separation of I and internal standard (IS) was achieved using a BDS Hypersil C8 analytical column, with a mobile phase consisting of acetonitrile:methanol:water (50:4:46) and trifluoroacetic acid (0.05%) at a flow rate of 0.6 ml/min. MS/MS detection was performed on a PE-Sciex API 300 tandem mass spectrometer operated in selected reaction monitoring mode. The parent-->product ions monitored were m/z 406-->195 for analyte I and m/z 448-->195 for the internal standard. Unusual in this method is that quantitation is accomplished using a secondary product ion, m/z 195, of drug I and IS. The assays were validated over the concentration range of 0.5-1000 ng/ml (1.2 nM to 2.5 microM, respectively) in plasma, and 2.5-500 ng/ml (6.2 nM to 1.23 microM) in urine. Accuracy was within +/-10% of nominal concentration at all levels in urine, and all but the lowest standard in plasma (+/-14% at 0.5 ng/ml). Intraday precision (expressed as coefficients of variation, CVs) for standard replicates and interday precision for quality control (QC) samples were less than 8% at all concentrations in both matrices. Detailed descriptions of the extraction procedure and analytical methodology used in the assay of I in plasma and urine are presented. This procedure may have utility in the quantitation of other imidazole-based FTIs with cyanobenzyl substructures.
为支持癌症患者的临床药代动力学研究，开发并验证了用于测定人血浆和尿液中4-[1-(4-氰基苄基)-5-咪唑基甲基]-1-(3-氯苯基)哌嗪酮（I）（一种法尼基转移酶抑制剂（FTI））的灵敏且特异的方法。这些方法基于高效液相色谱（HPLC），采用大气压化学电离（APCI）和串联质谱（MS/MS）检测，以正离子模式通过加热雾化器接口进行。使用氰基柱自动固相萃取从血浆或碱化尿液中分离药物和内标。有机提取物经干燥后，用乙腈水溶液复溶并注入系统。使用BDS Hypersil C8分析柱实现I和内标的色谱分离，流动相由乙腈:甲醇:水（50:4:46）和0.05%三氟乙酸组成，流速为0.6 ml/min。在选定反应监测模式下，使用PE-Sciex API 300串联质谱仪进行MS/MS检测。监测的母离子→子离子对为分析物I的m/z 406→195和内标的m/z 448→195。该方法的不同寻常之处在于，使用药物I和内标的二级产物离子m/z 195进行定量。该测定法在血浆浓度范围为0.5 - 1000 ng/ml（分别为1.2 nM至2.5 μM）和尿液浓度范围为及2.5 - 500 ng/ml（6.2 nM至1.23 μM）内得到验证。尿液中所有浓度水平的准确度在标称浓度的±10%以内，血浆中除最低标准（0.5 ng/ml时为±14%）外的所有标准的准确度也在该范围内。两种基质中所有浓度下标准品重复测定的日内精密度（以变异系数，CV表示）和质量控制（QC）样品的日间精密度均小于8%。文中给出了血浆和尿液中I测定所使用的提取程序和分析方法的详细描述。该程序可能对定量其他具有氰基苄基亚结构的基于咪唑的FTIs有用。
