在pH5.50的B-R缓冲溶液中,刚果红与马来酸罗格列酮(RGM)互相作用,形成2比1离子缔合物,导致刚果红试剂的色泽褪去,即在刚果红的吸收峰494 nm处,随RGM浓度增加反应体系的正吸光度降低,或负吸光度增加。试验表明:在此波长处,RGM浓度在7.20×10-6mol·L-1以内遵守比耳定律,表观摩尔吸光率为4.75×104L·mol-1·cm-1,检出限(3s)为4.36×10-7mol·L-1。方法可用于马来酸罗格列酮片和尿样中RGM含量的测定,测定值与高效液相色谱法测定值相符,回收率在102.7%~104.2%之间。

In a B-R buffer solution of pH 5.50, an ion-association complex was formed by the reaction of congo red with rosiglitazone maleate (RGM) with the molar ratio of 2 to 1, leading to decoloration of the congo red reagent, i.e., at the wavelength, 494 nm, the absorption maximum of congo red, the values of positive absorbance of the reaction system decrease with the increase of concentration of RGM, or on the other side, an increase of negative absorbance was observed. As shown by experiment. Beer′s law was obeyed in the concentration range within 7.20×10-6mol·L-1 of RGM, and the apparent molar absorptivity found was 4.75×104L·mol-1·cm-1. Value of detection limit (3s) found was 4.36×10-7mol·L-1. The proposed method was applied to the determination of RGM in RGM tablet and human urine, giving results in consistency with those obtained by HPLC. Values of recovery found were in the range of 102.7%-104.2%.