Abstract：
Preclinical studies have demonstrated that liposomal irinotecan (CPT-11), a topoisomerase I inhibitor, has broad activity against adult cancers, including pancreatic, gastric, colon, lung, glioma, ovarian, and breast cancer. Encapsulation of irinotecan into liposomes can modify its pharmacokinetic properties dramatically. Also, the pharmacokinetic profiles of liposomal drug formulations are not fully understood; thus, bioanalytical methods are needed to separate and quantify nonencapsulated vs. encapsulated concentrations. In this study, two robust, specific, and sensitive LC-MS/MS methods were developed and validated to separate and quantify the nonencapsulated CPT-11 (NE-CPT-11) from the sum-total CPT-11 (T-CPT-11) and its major metabolite, SN-38, in human plasma after intravenous administration of liposomal irinotecan. NE-CPT-11 and SN-38 were separated from plasma samples by using solid-phase extraction, and T-CPT-11 was measured by protein precipitation. The liposomal CPT-11 formulation was unstable during sample storage and handling, resulting in elevated NE-CPT-11 concentration. To improve the stability of liposomal CPT-11, a cryoprotectant solution was added to human plasma samples prior to storage and processing. CPT-11, SN-38, and their respective internal standards, CPT-11-d10 and SN-38-d3, were chromatographically separated on a reversed-phase C18 analytical column. The drugs were detected on a triple quadrupole mass spectrometer in the positive MRM ion mode by monitoring the transitions 587.3 > 124.1 (CPT-11) and 393.0 > 349.1 (SN-38). The calibration curves demonstrated a good fit across the concentration ranges of 10-5000 ng/mL for T-CPT-11, 2.5-250 ng/mL for NE-CPT-11, and 1-500 ng/mL for SN-38. The accuracy and precision were within the acceptable limits, matrix effects were nonsignificant, recoveries were consistent and reproducible, and the analytes were stable under all tested storage conditions. Finally, the LC-MS/MS methods were successfully applied in a phase I clinical pharmacokinetic study of nanoliposomal irinotecan (Onivyde®) in pediatric patients with recurrent solid malignancies or Ewing sarcoma.
摘要：
临床前研究表明，脂质体伊立替康（CPT-11），拓扑异构酶I抑制剂，对成人癌症有广泛的活性，包括胰腺,胃,结肠,肺，神经胶质瘤,卵巢,和乳腺癌。将伊立替康包封到脂质体中可以显着改变其药代动力学特性。此外，脂质体药物制剂的药代动力学特征尚未完全了解；因此，需要生物分析方法来分离和量化非包封与封装浓度。在这项研究中,两个健壮的，具体,开发和验证了灵敏的LC-MS/MS方法，以从总CPT-11（T-CPT-11）及其主要代谢物中分离和定量未包封的CPT-11（NE-CPT-11），脂质体伊立替康静脉内给药后人血浆中的SN-38。通过使用固相萃取从血浆样品中分离NE-CPT-11和SN-38,和T-CPT-11通过蛋白沉淀测量。脂质体CPT-11制剂在样品储存和处理过程中不稳定，导致NE-CPT-11浓度升高。为了提高脂质体CPT-11的稳定性,在储存和加工之前将冷冻保护剂溶液加入人血浆样品中。CPT-11、SN-38及其各自的内部标准，CPT-11-d10和SN-38-d3在反相C18分析柱上进行色谱分离。通过监测跃迁587.3>124.1(CPT-11)和393.0>349.1(SN-38),在正MRM离子模式下在三重四极质谱仪上检测药物。校准曲线证明在T-CPT-11的10-5000ng/mL、NE-CPT-11的2.5-250ng/mL和SN-38的1-500ng/mL的浓度范围内具有良好的拟合。准确度和精密度在可接受的范围内，基质效应不显著，回收率一致且可重复，并且分析物在所有测试的储存条件下都是稳定的。最后,LC-MS/MS方法成功应用于患有复发性实体恶性肿瘤或尤因肉瘤的儿科患者纳米脂质体伊立替康(Onivyde®)的I期临床药代动力学研究.
