Piperacillin, in combination with tazobactam is a common first-line antibiotic used for the treatment of pleural infection, however its pleural pharmacokinetics and penetration has not previously been reported. The objective of this work was to develop and validate a rapid and sensitive liquid chromatography with tandem mass spectrometry (LC-MS/MS) assay for quantification of piperacillin (PIP) and tazobactam (TAZ). PIP and TAZ were extracted from both human plasma and pleural fluid samples by protein precipitation in methanol containing the internal standards (IS) piperacillin-d₅ (PIP-d₅) and sulbactam (SUL). Briefly, 5 μL of sample was mixed with 125 μL of methanol containing IS, vortexed and centrifuged. Supernatant (50 μL) was diluted into 500 μL of mobile phase containing 10 mM of ammonium bicarbonate in LCMS grade water and transferred to the autosampler tray. Electrospray ionization in positive mode and multiple reaction monitoring (MRM) were used for PIP and PIP-d₅ at the transitions m/z 518.2 → 143.2 and m/z 523.2 → 148.2 respectively, and electrospray ionization in negative mode and MRM were used for TAZ and SUL at the transitions m/z 299.1 → 138.1 and m/z 232.4 → 140.1. The chromatographic separation was achieved using an Acquity BEH C-18 column with gradient elution of mobile phase containing 10 mmol/L ammonium bicarbonate in water and methanol. A linear range was observed over the concentration range of 0.25–352 mg/L and 0.25–50.5 mg/L for PIP and TAZ respectively. Complete method validation was performed according to US FDA guidelines for selectivity, specificity, precision and accuracy, LLOQ, matrix effects, recovery and stability, with all results within acceptable limits. This method was successfully applied to two patients with pleural infection and is suitable for further pharmacokinetic studies and therapeutic drug monitoring.

哌拉西林与他唑巴坦联用是用于治疗胸膜感染的常见一线抗生素，但是以前尚未报道其胸膜药代动力学和渗透性。这项工作的目的是开发和验证一种快速灵敏的液相色谱-串联质谱（LC-MS / MS）分析法，用于定量哌拉西林（PIP）和他唑巴坦（TAZ）的定量。通过在含有内标（IS）哌拉西林-d ₅（PIP-d ₅）的甲醇中进行蛋白质沉淀，从人血浆和胸水样品中提取PIP和TAZ）和舒巴坦（SUL）。简而言之，将5μL样品与125μL含IS的甲醇混合，涡旋并离心。将上清液（50μL）稀释到500μL的LCMS级水中含有10 mM碳酸氢铵的流动相中，并转移到自动进样器托盘中。PIP和PIP-d ₅分别在跃迁m / z 518.2→143.2和m / z 523.2→148.2时使用正模式电喷雾电离和多反应监测（MRM），负模式和MRM分别使用负电喷雾电离和MRM TAZ和SUL在过渡m / z 299.1→138.1和m / z时232.4→140.1。使用Acquity BEH C-18色谱柱，在水和甲醇中含10 mmol / L碳酸氢铵的流动相进行梯度洗脱，进行色谱分离。对于PIP和TAZ，在0.25-352 mg / L和0.25-50.5 mg / L的浓度范围内分别观察到线性范围。根据美国FDA关于选择性，特异性，精密度和准确性，LLOQ，基质效应，回收率和稳定性的指南进行了完整的方法验证，所有结果均在可接受的范围内。该方法已成功应用于两名胸膜感染患者，适用于进一步的药代动力学研究和治疗药物监测。