Pitié Salpetrière Hospital - AP-HP, Pharmacy Department, 47, Boulevard de l'hôpital, 75013 Paris, France.
J Pharm Biomed Anal. 2012 Jul;66:325-33. doi: 10.1016/j.jpba.2012.04.003. Epub 2012 Apr 11.
A sensitive and accurate liquid chromatography method with mass spectrometry detection using MRM in positive ion mode was developed and validated for the simultaneous quantification of irinotecan (CPT-11) and 7-ethyl-10-hydroxycamptothecin (SN-38) in mouse plasma and brain. Camptothecin (CPT) was used as internal standard. A single step protein precipitation was used for plasma sample preparation, and a liquid-liquid extraction was needed for brain sample preparation. The method was validated with respect to selectivity, extraction recovery, linearity, intra- and inter-day precision and accuracy, limit of quantification and stability. Limits of quantification were 5 ng/mL for CPT-11 and SN-38 in plasma samples and 1.25 ng/g in brain. Linear calibration curves were obtained over concentration ranges of 5-5000 ng/mL in plasma and 1.25-1250 ng/g in brain for CPT-11 and SN-38. The intra-day and inter-day variation (relative standard deviation, R.S.D.) found to be less than 15% for both substances in both media. Stability studies showed that plasma carboxylesterase had to be inactivated in order to prevent in vitro conversion of CPT-11 into SN-38. Zinc sulfate (1 M) was used to inactivate the enzyme before sample storage. Brain samples did not require enzyme inactivation. This method was successfully applied to perform brain and plasma pharmacokinetic studies of CPT-11 and SN-38 in mice after intraperitoneal administration.
建立并验证了一种灵敏、准确的液质联用 MRM 正离子检测法，用于同时定量检测小鼠血浆和脑组织中的伊立替康（CPT-11）和 7-乙基-10-羟基喜树碱（SN-38）。喜树碱（CPT）作为内标。采用单一的蛋白沉淀法用于血浆样品制备，而脑样品则需要液液萃取。该方法在选择性、提取回收率、线性、日内和日间精密度和准确度、定量下限和稳定性方面进行了验证。CPT-11 和 SN-38 在血浆样品中的定量下限为 5ng/mL，在脑组织中的定量下限为 1.25ng/g。CPT-11 和 SN-38 在血浆中的浓度范围为 5-5000ng/mL，在脑组织中的浓度范围为 1.25-1250ng/g 时，均获得了线性校准曲线。在两种介质中，两种物质的日内和日间变化（相对标准偏差，R.S.D.）均小于 15%。稳定性研究表明，为了防止 CPT-11 在体外转化为 SN-38，必须使血浆中的羧酸酯酶失活。在样品储存前，使用硫酸锌（1M）使酶失活。脑样品不需要酶失活。该方法成功应用于研究腹腔注射 CPT-11 和 SN-38 后小鼠的脑和血浆药代动力学。
