6-Thioguanine is an immunosuppressive drug, an analogue of guanine, applied to treat acute leukemia and inflammatory bowel disease. Excessive use of 6-thioguanine during clinical treatment may cause side effects. Moreover, providing a dose too low will be ineffective. Therefore, there is a critical need for a rapid, selective and routine approach to quantifying 6-thioguanine in body fluids to support a clinical application. A fully validated HPLC method has been developed to determine 6-thioguanine in whole blood samples using 5-bromouracil as an internal standard. 6-Thioguanine nucleotides were released from erythrocytes by perchloric acid, and then hydrolysed at 100 °C to the parent thiopurine, 6-thioguanine. The following validation parameters of the method were determined: specificity/selectivity, linearity range (479–17,118 ng/mL, R > 0.992), limits of detection (150 ng/mL) and quantification (479 ng/mL), accuracy (− 5.6 < Bias < 14.7), repeatability (CV 1.30–3.24%), intermediate precision (CV 4.19–5.78%), extraction recovery (79.1–103.6%) and carryover. Furthermore, the stability of the drug in whole blood samples under various storage conditions was investigated. The suggested method is suitable for determining 6-thioguanine in whole blood erythrocyte samples for drug level monitoring, thus correct dosing.

6-硫鸟嘌呤是一种免疫抑制药物，是鸟嘌呤的类似物，用于治疗急性白血病和炎症性肠病。临床治疗过程中过量使用6-硫鸟嘌呤可能会引起副作用。此外，提供太低的剂量将是无效的。因此，迫切需要一种快速、选择性和常规的方法来定量体液中的 6-硫鸟嘌呤以支持临床应用。已开发出一种经过充分验证的 HPLC 方法，可使用 5-溴尿嘧啶作为内标测定全血样品中的 6-硫鸟嘌呤。6-硫鸟嘌呤核苷酸通过高氯酸从红细胞中释放出来，然后在 100 °C 下水解为母体硫嘌呤，6-硫鸟嘌呤。确定了该方法的以下验证参数：特异性/选择性、线性范围（479–17,118 ng/mL，R > 0.992）、检测限（150 ng/mL）和定量（479 ng/mL）、准确度（− 5.6 < 偏倚 < 14.7)、重复性 (CV 1.30–3.24%)、中间精密度 (CV 4.19–5.78%)、提取回收率 (79.1–103.6%) 和残留。此外，还研究了不同储存条件下全血样品中药物的稳定性。该方法适用于测定全血红细胞样本中的 6-硫鸟嘌呤，用于药物浓度监测，从而正确给药。