高效液相色谱-质谱联用测定大鼠血浆及组织中奥昔布宁浓度

HPLC-MS determination of oxybutynin in plasma and tissue of rats

目的:建立大鼠血浆和组织奥昔布宁浓度测定方法,进行奥昔布宁凝胶剂药代动力学研究。方法:48只大鼠随机分为两组,片剂单剂灌胃0.5 mg,2%凝胶剂腹部涂敷1g,一定时间点取血浆、膀胱和肾脏,采用液相色谱-质谱法测定奥昔布宁经时血浓度。ZORBAX Extend-C_(18)柱(2.1 mm×150 mm,5μm),流动相为乙腈及0.1%醋酸-pH 5.4醋酸铰缓冲液(50:50),流速为0.5 mL·min^(-1),分流比2:1,进样量20μL。质谱检验参数如下:AP-ESI 正离子模式,雾化压力2.07 MPa,保护气:N_2,流量:10 L·min^(-1),毛细管电压4000 V,离子源温度100℃,碎片电压为130 V,采集方式为 SIM,采集离子奥昔布宁m/z 358.2。结果:在0.5～50 ng·mL^(-1)范围内线性关系良好,最低检测限为0.15 ng·mL^(-1),提取回收率大于70%,日内 RSD小于8.87%,日间 RSD 小于10.01%。动力学研究结果:盐酸奥昔布宁凝胶剂和片剂膀胱组织与血浆浓度比值分别为816.91和71.53,AUC_(0～∞)比值分别为726.96和84.56;凝胶剂半衰期延长。结论:方法专属性强、灵敏度高,适用于奥昔布宁凝胶剂的药代动力学研究。盐酸奥昔布宁凝胶剂有效作用时间长,靶组织浓度高。

Objective： To establish an HPLC - MS method for determining the oxybutynin concentration in plasma and tissue and to evaluate the pharmacokinetic of oxybutynin gel. Methods： Oxybutynin was administered either as a single 0.5 mg tablet or as a single 1 g gel to 48 rats in a randomized design. Blood bladder and liver samples were collected and assayed by LC - MS. A ZORBAX Extend - C18 column was used to separate oxybutynin in plasma and tissue with a mobile phase of a mixture of acetonitrile 0.1% - pH5.4 acetic acid buffer （50：50） at a flow rate of 0.5 mL·min^-1. Atmosperic pressure electronic spray ionization （AP - ESI） and ion mass spectral （m/z） of 358.2 were selected to quantify oxybutynin. Results： The linear range of the standard curve of oxybutynin was 0.5 - 50 ng·mL^-1. The determination limit was 0.15 ng·mL^-1. The extraction recovery was more than 70%. Intra - day and inter - day RSD were less than 8.87% and 10.01%. The mean concentration in bladder and plasma rations of gel and tablet were 816.91 and 71.53, AUC0-∞ rations were 726.96 and 84.56 respectively. Conclusion： It can be concluded that the method is sensitive, rapid and accurate. It is suitable for pharmacokinetic studies of oxybutynin gel. Oxybutynin gel compared to tablet resulted in not only a longer half life but also a higher bladder concentration.