Sample pretreatment included protein precipitation with methanol. For the measurement of protein-unbound flucloxacillin, ultrafiltration was performed at physiological temperature. For all compounds, a stable isotopically labelled internal standard was used. Reliability of the results was assessed by participation in an international quality control programme.
The assay was successfully validated according to the EMA guidelines over a concentration range of 0.5-100 mg/L for ceftazidime, 0.05-10 mg/L for ciprofloxacin, 0.4-125 mg/L for flucloxacillin, 0.2-60 mg/L for piperacillin, 0.15-30 mg/L for tazobactam, 1-200 mg/L for sulfamethoxazole and N-acetyl sulfamethoxazole, 0.05-10 mg/L for trimethoprim and 0.10-50 mg/L for unbound flucloxacillin. For measurement of total concentrations, the within- and between-day accuracy ranged from 90.0% to 109%, and 93.4% to 108%, respectively. Within- and between-day precision (variation coefficients, CVs) ranged from 1.70% to 11.2%, and 0.290% to 5.30%, respectively. For unbound flucloxacillin, within-day accuracy ranged from 103% to 106% and between-day accuracy from 102% to 105%. The within- and between-day CVs ranged from 1.92% to 7.11%. Results of the international quality control programme showed that the assay is reliable.
The method provided reliable, precise and accurate measurement of seven commonly prescribed antibiotics, including the unbound concentration of flucloxacillin. This method is now routinely applied in research and clinical practice.
方法:样品预处理包括用甲醇沉淀蛋白质。对于蛋白质未结合的氟氯西林的测量,超滤在生理温度下进行。对于所有化合物,使用稳定的同位素标记的内标.通过参与国际质量控制计划来评估结果的可靠性。
结果:根据EMA指南,头孢他啶的浓度范围为0.5-100mg/L,环丙沙星0.05-10mg/L,氟氯西林0.4-125毫克/升,哌拉西林为0.2-60mg/L,他唑巴坦为0.15-30毫克/升,1-200mg/L的磺胺甲恶唑和N-乙酰基磺胺甲恶唑,甲氧苄啶为0.05-10mg/L,未结合的氟氯西林为0.10-50mg/L。为了测量总浓度,日内和日间准确度范围从90.0%到109%,和93.4%到108%,分别。具有日内和日间精度(变异系数,CV)范围从1.70%到11.2%,和0.29%至5.30%,分别。对于未结合的氟氯西林,日内准确率为103%~106%,日内准确率为102%~105%.日内和日间简历的范围为1.92%至7.11%。国际质量控制计划的结果表明该测定法是可靠的。
结论:该方法提供了可靠的,精确准确地测量七种常用抗生素,包括氟氯西林的未结合浓度。该方法现已常规应用于研究和临床实践。