Division of Pharmacology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
Department of Pharmacy and Pharmacology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
Cancer Chemother Pharmacol. 2023 Mar;91(3):257-266. doi: 10.1007/s00280-023-04518-7. Epub 2023 Mar 11.
Measurement of endogenous uracil (U) is increasingly being used as a dose-individualization method in the treatment of cancer patients with fluoropyrimidines. However, instability at room temperature (RT) and improper sample handling may cause falsely increased U levels. Therefore we aimed to study the stability of U and dihydrouracil (DHU) to ensure proper handling conditions.
Stability of U and DHU in whole blood, serum, and plasma at RT (up to 24 h) and long-term stability (≥ 7 days) at - 20 °C were studied in samples from 6 healthy individuals. U and DHU levels of patients were compared using standard serum tubes (SSTs) and rapid serum tubes (RSTs). The performance of our validated UPLC-MS/MS assay was assessed over a period of 7 months.
U and DHU levels significantly increased at RT in whole blood and serum after blood sampling with increases of 12.7 and 47.6% after 2 h, respectively. A significant difference (p = 0.0036) in U and DHU levels in serum was found between SSTs and RSTs. U and DHU were stable at - 20 °C at least 2 months in serum and 3 weeks in plasma. Assay performance assessment fulfilled the acceptance criteria for system suitability, calibration standards, and quality controls.
A maximum of 1 h at RT between sampling and processing is recommended to ensure reliable U and DHU results. Assay performance tests showed that our UPLC-MS/MS method was robust and reliable. Additionally, we provided a guideline for proper sample handling, processing and reliable quantification of U and DHU.
在以氟嘧啶类药物治疗癌症患者的过程中，内源性尿嘧啶（U）的测量正越来越多地被用作剂量个体化的方法。然而，室温（RT）下的不稳定性和不当的样本处理可能导致 U 水平的假性升高。因此，我们旨在研究 U 和二氢尿嘧啶（DHU）的稳定性，以确保正确的处理条件。
在 6 名健康个体的样本中，研究了 U 和 DHU 在 RT（长达 24 小时）下全血、血清和血浆中的稳定性以及在-20°C 下的长期稳定性（≥7 天）。使用标准血清管（SST）和快速血清管（RST）比较了患者的 U 和 DHU 水平。评估了我们经过验证的 UPLC-MS/MS 测定法在 7 个月的时间内的性能。
在采血后 2 小时，全血和血清中的 U 和 DHU 水平在 RT 下分别显著增加了 12.7%和 47.6%。SST 和 RST 之间血清中 U 和 DHU 水平存在显著差异（p=0.0036）。U 和 DHU 在血清中至少在-20°C 下稳定至少 2 个月，在血浆中稳定至少 3 周。测定性能评估符合系统适用性、校准标准和质量控制的验收标准。
建议在采样和处理之间，在 RT 下的最长时间为 1 小时，以确保可靠的 U 和 DHU 结果。测定性能测试表明，我们的 UPLC-MS/MS 方法是稳健可靠的。此外，我们提供了适当的样本处理、处理和可靠定量 U 和 DHU 的指南。
