Toral M Inés, Tassara Andrés, Soto César, Richter Pablo
University of Chile, Laboratory of Analytical Chemistry, Department of Chemistry, Faculty of Sciences, PO Box 653, Santiago, Chile.
J AOAC Int. 2003 Mar-Apr;86(2):241-5.
A simple and fast method was developed for the simultaneous determination of dapsone and pyrimethamine by first-order digital derivative spectrophotometry. Acetonitrile was used as a solvent to extract the drugs from the pharmaceutical formulations, and the samples were subsequently evaluated directly by digital derivative spectrophotometry. The simultaneous determination of both drugs was performed by the zero-crossing method at 249.4 and 231.4 nm for dapsone and pyrimethamine, respectively. The best signal-to-noise ratio was obtained when the first derivative of the spectrum was used. The linear range of determination for the drugs was from 6.6 x 10(-7) to 2.0 x 10(-4) and from 2.5 x 10(-6) to 2.0 x 10(-4) mol/L for dapsone and pyrimethamine, respectively. The excipients of commercial pharmaceutical formulations did not interfere in the analysis. Chemical and spectral variables were optimized for determination of both analytes. A good level of repeatability, 0.6 and 1.7% for dapsone and pyrimethamine, respectively, was observed. The proposed method was applied for the simultaneous determination of both drugs in pharmaceutical formulations.
建立了一种简单快速的一阶数字导数分光光度法同时测定氨苯砜和乙胺嘧啶的方法。以乙腈为溶剂从药物制剂中提取药物，随后直接用数字导数分光光度法对样品进行评估。分别在249.4和231.4 nm处采用零交叉法同时测定两种药物，氨苯砜和乙胺嘧啶分别对应这两个波长。使用光谱的一阶导数时获得了最佳信噪比。两种药物的线性测定范围分别为氨苯砜6.6×10⁻⁷至2.0×10⁻⁴mol/L以及乙胺嘧啶2.5×10⁻⁶至2.0×10⁻⁴mol/L。市售药物制剂中的辅料不干扰分析。对两种分析物的测定优化了化学和光谱变量。观察到良好的重复性水平，氨苯砜和乙胺嘧啶的重复性分别为0.6%和1.7%。所提出的方法用于同时测定药物制剂中的两种药物。
