Abstract：
This study developed and validated a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify omadacycline and its epimerization in stool to facilitate microbiome studies. Omadacycline was extracted in a methanol-water-ethylenediaminetetraacetic acid (ETDA) solvent containing deuterated omadacycline as internal standard, followed by dilution. In an optimal gradient elution mode, omadacycline and its C4 epimer were separated within 5 min on reversed-phase C18 column. The method showed a broad working range of 0.1-200 ng/ml with a limitation of detection (LOD) of 0.03 ng/ml, little fecal matrix effect, good intra-day and inter-day accuracy (90-101 %), precision (2-15 %), and recovery rate (99-105 %). The method was sufficiently sensitive to quantify omadacycline in human fecal samples (n = 82) collected during a 10-day therapy course and at follow-up (day 13 and day 30) that ranged from 1 to 4785 µg/g. Further analysis revealed that ∼9 % of omadacycline was epimerized in fecal matrix control while, on average, 37.4 % was epimerized in human fecal samples. This study developed and validated a novel, simple, sensitive, and accurate method utilizing LC-MS/MS to quantify omadacycline its epimerization in the human gut. This has important implications for future studies of omadacycline and other tetracycline-class antibiotics as part of gut microbiome studies.
摘要：
这项研究开发并验证了一种新的液相色谱-串联质谱（LC-MS/MS）方法，以量化粪便中的奥马环素及其差向异构化，以促进微生物组研究。在含有氘代奥马环素作为内标的甲醇-水-乙二胺四乙酸（ETDA）溶剂中提取奥马环素，其次是稀释。在最佳梯度洗脱模式下，奥马环素及其C4差向异构体在反相C18色谱柱上在5分钟内分离。该方法显示了0.1-200ng/ml的宽工作范围，检测限制（LOD）为0.03ng/ml，粪便基质效应很小，良好的日内和日间准确性（90-101%），精度（2-15%），和回收率（99-105％）。该方法足够灵敏，可以量化在10天治疗过程中和随访（第13天和第30天）收集的人类粪便样品（n=82）中的奥马环素，范围为1至4785µg/g。进一步的分析表明，在粪便基质控制中，~9%的奥马环素被差向异构化，而，平均而言,在人类粪便样品中，有37.4％被差向异构化。这项研究开发并验证了一种新颖的，简单,敏感,利用LC-MS/MS定量奥马环素在人体肠道中的差向异构化的准确方法。这对未来奥马环素和其他四环素类抗生素作为肠道微生物组研究的一部分的研究具有重要意义。
