用分光光度法研究了盐酸二甲双胍和瑞格列奈作为电子给予体分别与电子接受体四氯苯醌的荷移反应.确定反应及测定的条件:在硼砂与氢氧化钠缓冲溶液中,二甲双胍、瑞格列奈分别与四氯苯醌混匀于25 ℃水浴中恒温15 min,可形成1∶1的有色稳定荷移络合物,在可见光区的最大吸收波长分别为λ二甲双胍=695 nm,λ瑞格列奈=718 nm,表观摩尔吸光率分别为ε二甲双胍=4.11×104L·mol-1·cm-1,ε瑞格列奈=3.08×104L·mol-1·cm-1,二甲双胍在1.0×10-3mol·L-1以内遵从比耳定律,而瑞格列奈在2.0×10-4mol·L-1以内遵从比耳定律.应用此法测定市售的药物制剂的测得含量与药典方法所测得结果一致(经t检验证实).二甲双胍和瑞格列奈的平均回收率分别为98.6%和102.8%,二甲双胍和瑞格列奈测定结果的相对标准偏差均小于3.5%.

Charge transfer reactions between either of the 2 hyperglycaemia drugs,metformin hydrochloride and repaglinide (as electron donor) and tetrachlorobenzoquinone (as electron acceptor) were studied spectrophotometrically.In a borax buffer of pH 9-10,a colored and stable charge transfer complex,with molar ratio of 1 to 1 was formed between either the metformin or repaglinide and tetrachlorobenzoquinone,when the reactants were kept in a water bath at 25 ℃ for 15 min.Absorption maxima of the complex of metformin was found at the wavelength of 695 nm,and of the complex of repaglinide at the wavelength of 718 nm.Linearity of the calibration curve was found in the range within 1.0×10-3mol·L-1 for metformin and in the range within 2.0×10-4mol·L-1 for repaglinide,with values of apparent molar absorptivity 4.11×104L·mol-1·cm-1 and 3.08×104 L·mol-1·cm-1 respectively.The proposed method was applied to the analysis of 3 drug samples,giving results in consistency with the results of pharmacopoeia method (as proved by t-test),and values of RSD′s (n=5) less than 3.5%.Results of test for recovery obtained were 98.6% (average) for metformin and 102.8% (average) for repaglinide.