高效毛细管电泳前沿分析法研究酸性药物那格列奈与人血浆白蛋白的结合

Study of Protein Binding of Acidic Drug, Nateglinide, in Human Plasma Albumin Solution by High Performance Capillary Electrophoresis/Frontal Analysis

用高效毛细管电泳前沿分析法研究了酸性药物那格列奈与人血浆白蛋白的结合常数、结合位点和结合率。使用未涂层的毛细管柱 (4 0cm× 5 0 μmi.d .;有效柱长 32cm) ,磷酸盐缓冲溶液 (pH 7.4 ,离子强度0 .17)为背景溶液 ,在紫外检测波长 2 14nm、运行电压 18kV和重力进样 10 0s的条件下 ,利用那格列奈谱峰的平台高度和游离药物浓度的良好线性关系 (r>0 .999,n =6 ) ,测定了那格列奈的游离药物浓度。固定药物浓度 (2 0 0 μmol L ,2 5 0 μmol L) ,考察不同的蛋白质浓度对结合的影响 ;固定蛋白质浓度 (10 0 μmol L) ,考察不同的药物浓度对结合的影响。实验数据采用非线性拟和程序进行处理 ,得到了那格列奈的蛋白质结合参数。高效毛细管电泳前沿分析法测定的数据重现性良好 (RSD <2 .5 % ,n =3) ,在药代动力学和药效学研究方面具有简便、准确的优点。

The protein binding constants, binding sites and binding rate of acidic drug, Nateglinide, in human Plasma albumin solution was studied by high performance capillary electrophoresis frontal analysis (HPCE/FA). The experiments were carried out by determining unbound drug concentration in drug-protein equilibrium solution in a uncoated fused silica capillary (40 cm x 50 mum i.d.; effective length 32 cm) for capillary electrophoresis under the following conditions: background solution, sodium phosphate buffer solution (pH 7.4, ionic strength 0.17); ultraviolet detector, wavelength 214 nm; hydrostatic injection mode and the injection time 100 s; run voltage 18 kV. The unbound drug concentration. was calculated from the plateau height of the profile with good linear relation, r > 0.9999 for nateglinide ( n = 6). The influence of different protein concentrations on the protein binding was investigated while the drug concentration (200 mumol/L, 250 mumol/L) was fixed. Similarly, the effect of different drug concentrations on protein binding was also studied while the protein concentration ( 100 mumol/L) was fixed. The experimental data were fitted by a non-linear least-squares curve fitting program and binding parameters were obtained simultaneously. The precision of the data determined by HPCE/FA was RSD (RSD < 2.5% n = 3). The capillary electrophoresis frontal analysis presents an easy, accurate. method for pharmacokinetics and pharmacodynamics study of the drug.