Adegoke Olajire Aremu, Idowu Olakunle Sunday, Olaniyi Ajibola Akinyemi
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Ibadan, Nigeria.
Acta Pharm. 2006 Jun;56(2):189-202.
A simple, sensitive and direct colorimetric method for the determination of indomethacin either in pure form or in capsules has been developed. The method is based on the diazo coupling reaction between indomethacin and a highly reactive arenediazonium ion, 4-carboxyl-2,6-dinitrobenzene diazonium ion, with the consequent formation of an azo dye. The reaction is fast and gave an orange azo dye in ethyl acetate. The assay was carried out at 470 nm and the azo adduct was stable for three hours. Beer's law is obeyed in the concentration range of 3.3-11 microg mL(-1) of indomethacin. Optimization studies established an optimum reaction time of 20 minutes at 30 degrees C and the drug-to-reagent ratio of 1:2 for optimal detector response. The method developed has a low limit of detection of 0.90 microg mL(-1) and is precise (RSD 2.3%). The new method has been successfully applied to the determination of indomethacin in capsules and the method is of equivalent accuracy as the official (BP) spectrophotometric method. The new method could find application as a simple analytical method for the assay of indomethacin in capsules.
已开发出一种简单、灵敏且直接的比色法，用于测定纯品或胶囊中的吲哚美辛。该方法基于吲哚美辛与高活性芳基重氮离子4-羧基-2,6-二硝基苯重氮离子之间的重氮偶合反应，从而形成偶氮染料。反应迅速，在乙酸乙酯中生成橙色偶氮染料。在470nm处进行测定，偶氮加合物在三小时内稳定。在吲哚美辛浓度为3.3 - 11μg mL(-1)范围内符合比尔定律。优化研究确定在30℃下最佳反应时间为20分钟，药物与试剂比例为1:2时检测器响应最佳。所开发的方法检测限低至0.90μg mL(-1)，精密度高（相对标准偏差为2.3%）。该新方法已成功应用于胶囊中吲哚美辛的测定，且与官方（BP）分光光度法具有同等准确度。该新方法可作为一种简单的分析方法用于胶囊中吲哚美辛的含量测定。
