Chiap P, Evrard B, Bimazubute M A, de Tullio P, Hubert P, Delattre L, Crommen J
Department of Analytical Pharmaceutical Chemistry, Institute of Pharmacy, University of Liège, Belgium.
J Chromatogr A. 2000 Feb 18;870(1-2):121-34. doi: 10.1016/s0021-9673(99)00938-3.
Albendazole is a benzimidazole derivative with a broad-spectrum activity against human and animal helminth parasites. In order to determine the main pharmacokinetic parameters in sheep after oral and intravenous administration of a new formulation of albendazole (an aqueous solution), a fully automated method was developed for the determination of this drug and its main metabolites, albendazole sulfoxide (active metabolite) and sulfone in ovine plasma. This method involves dialysis as purification step, followed by enrichment of the dialysate on a precolumn and liquid chromatography (LC). All sample handling operations were executed automatically by means of an ASTED XL system. After conditioning of the trace enrichment column (TEC) packed with octadecyl silica with pH 6.0 phosphate buffer containing sodium azide, the plasma sample, in which a protein releasing reagent (1 M HCl) containing Triton X-100 was automatically added, was loaded in the donor channel and dialysed on a cellulose acetate membrane in the static-pulsed mode. The dialysis liquid consisted of pH 2.5 phosphate buffer. By rotation of a switching valve, the analytes were eluted from the TEC in the back-flush mode by the LC mobile phase and transferred to the analytical column, packed with octyl silica. The chromatographic separation was performed at 35 degrees C and the analytes were monitored photometrically at 295 nm. Due to the differences in hydrophobic character between albendazole and its metabolites, a gradient elution was applied. The mobile phase consisted of a mixture of acetonitrile and pH 6.0 phosphate buffer. The proportion of organic modifier was increased from 10.0 to 50.1% in 12.30 min, then from 50.1 to 66.9% in 1.70 min. First, the gradient conditions and the temperature were optimised for the LC separation using the DryLab software. Then, the influence of some parameters of the dialysis process on analyte recovery was investigated. Finally, the method developed was validated. The mean recoveries for albendazole and its metabolites were about 70 and 65%, respectively. The limits of quantification for albendazole and its metabolites were 10 and 7.5 ng/ml, respectively.
阿苯达唑是一种苯并咪唑衍生物，对人和动物的蠕虫寄生虫具有广谱活性。为了确定口服和静脉注射阿苯达唑新制剂（一种水溶液）后绵羊体内的主要药代动力学参数，开发了一种全自动方法来测定绵羊血浆中的该药物及其主要代谢物阿苯达唑亚砜（活性代谢物）和砜。该方法包括透析作为纯化步骤，然后将透析液在预柱上富集并进行液相色谱（LC）分析。所有样品处理操作均通过ASTED XL系统自动执行。在用含有叠氮化钠的pH 6.0磷酸盐缓冲液对填充有十八烷基硅胶的微量富集柱（TEC）进行预处理后，将自动添加含有Triton X-100的蛋白质释放试剂（1 M HCl）的血浆样品加载到供体通道中，并在醋酸纤维素膜上以静态脉冲模式进行透析。透析液由pH 2.5磷酸盐缓冲液组成。通过旋转切换阀，分析物通过LC流动相以反冲模式从TEC中洗脱，并转移到填充有辛基硅胶的分析柱上。色谱分离在35℃下进行，分析物在295nm处进行光度监测。由于阿苯达唑及其代谢物在疏水特性上的差异，采用了梯度洗脱。流动相由乙腈和pH 6.0磷酸盐缓冲液的混合物组成。有机改性剂的比例在12.30分钟内从10.0%增加到50.1%，然后在1.70分钟内从50.1%增加到66.9%。首先，使用DryLab软件对LC分离的梯度条件和温度进行了优化。然后，研究了透析过程中一些参数对分析物回收率的影响。最后，对所开发的方法进行了验证。阿苯达唑及其代谢物的平均回收率分别约为70%和65%。阿苯达唑及其代谢物的定量限分别为10和7.5 ng/ml。
