HPLC-DAD-MSn 法分析恩诺沙星在兔血浆中的代谢产物

采用HPLC-DAD-MSn法对兔肌注恩诺沙星给药后血浆中恩诺沙星和代谢产物的紫外光谱和质谱裂解行为进行分析,获得各化合物的光谱和多级质谱信息。比较给药前后兔血浆的DAD检测色谱图,发现6个可能的代谢产物M1……M6。根据化合物结构和质谱裂解途径及标准品的色谱保留时间,确定M3为环丙沙星,并推测M5可能为加氧恩诺沙星;M4获得一级质谱数据和紫外光谱数据;M1、M2和M6仅得到紫外光谱数据。推测恩诺沙星在兔体内的主要代谢反应是脱乙基反应和氧化反应。

Analysis on the Metabolites of Enrofloxacin in the Plasma of Rabbit by HPLC-DAD-MSn

The enrofloxacin and its metabolites in the plasma of rabbit following intramuscular injection, were analyzed using HPLC integrated diode array detector(DAD) and electrospray ion(ESI) trap mass spectrometry in a multistage MS full scan mode. Six potential metabolites, M1 to M6 were found by comparing the chromatogram of DAD of the plasma in rabbits before and post injecting enrofloxacin, which have similar ultraviolet spectrum to enrofloxacin. The multistage mass spectral information was obtained following the mass spectrometric analysis of enrofloxacin and its metabolites (M3 and M5) by collision induced dissociation. The result showed that enrofloxacin was biotransformed to six metabolites in the plasma. In which, the structure of two metabolites, ciprofloxacin was identified and oxyenrofloxacin was speculated. The main mechanism of biotransformed for enrofloxacin may be dethylation and oxidation effects.