Simultaneous Determination of Sulfamethoxazole and Trimethoprim Using UV Spectroscopy in Combination with Multivariate Calibration

The objective of this study is to evaluate the capability of UV-spectrophotometry in combination of multivariate calibration based on Partial Least Square (PLS) regression for simultaneous quantitative analysis and dissolution evaluation of sulfamethoxazole (SUL) and trimethoprim (TRI) in tablet dosage form.The experimental calibration and validation matrixes were constructed with 20 and 10 samples, respectively.The concentration range considered was 1-16 µg mLG 1 for both SUL and TRI.The absorbance data of the calibration standards were taken between 200-400 nm.For achieving the best calibration model, the related parameters were evaluated.The optimum number of factors was selected by using the cross-validation method.The evaluation of calibration model is relied on the coefficient of determination (R 2 ) and Root Mean Square Error of Calibration (RMSEC).The coefficient of determination (R 2 ) for the relationship between actual values and predicted values of SUL and TRI was higher than 0.99 indicating good accuracy of the developed method.The RMSEC values obtained were relatively low, namely 0.167% (SUL) and 0.279% (TRI), which indicate acceptable precision of analytical method.The accuracy of developed method was comparable to that of High Performance Liquid Chromatography (HPLC) method.The UV spectrophotometry in combination with PLS calibration model was successfully used for quantitative analysis and dissolution studies of SUL and TRI sulfamethoxazole and trimethoprim in tablet dosage form.