液液萃取-荧光分析法测定注射剂中盐酸利多卡因的含量

Determination of Lidocaine Hydrochloride Injection by Liquid-Liquid Extraction-Fluorimetry

基于盐酸利多卡因在pH=4.0条件下的水解产物2,6-二甲基苯胺(DMA)的强荧光性质,建立了一种测定盐酸利多卡因药物含量的新方法。考察了溶剂对DMA光谱性质的影响,结果表明随着溶剂极性的增强,其荧光光谱和吸收光谱强度均下降。在乙醚溶剂中,DMA在305nm激发波长下于324nm处有最强的荧光发射峰,明显区别于利多卡因水溶液的荧光发射峰。DMA的浓度与其荧光峰强度在一定范围内呈良好的线性关系,相关系数r=0.9975,检测限(3s/K)为9.72×10-8 mol/L。将该方法用于注射液中盐酸利多卡因含量的测定,与高效液相色谱法对照,结果吻合。

A new method for the determination of medicine concentration has been developed according to the fluorescent character of 2,6-methyltoluidine（DMA）that hydrolyzed by lidocaine hydrochloride in pH=4.00.The effects of different polarized solvent were investigated.The results showed that the fluorescence and absorption spectra of DMA ine polar solvent red-shifted and spectral intensity was weakened.DMA in ethyl ether had a maximum emission wavelength at 324 nm with exciatation at 305 nm,obvious different from lidocaine aqueous solution.A linear relationship was obtained between the relative fluorescence intensity and the concentration of DMA in a certain range,the correlation coefficient was 0.9975,and the detection limit of this method was 9.72×10^-8 mol/L（3s/K）.The method was applied to the detection of lidocaine hydrochloride in injection solution,and the results obtained by the method agreed with those by HPLC.