Simultaneous determination of some antiprotozoal drugs in different combined dosage forms by mean centering of ratio spectra and multivariate calibration with model updating methods

BACKGROUND Metronidazole (MET) and Diloxanide Furoate (DF), act as antiprotozoal drugs, in their ternary mixtures with Mebeverine HCl (MEH), an effective antispasmodic drug. This work concerns with the development and validation of two simple, specific and cost effective methods mainly for simultaneous determination of the proposed ternary mixture. In addition, the developed multivariate calibration model has been updated to determine Metronidazole benzoate (METB) in its binary mixture with DF in Dimetrol® suspension. RESULTS Method (I) is the mean centering of ratio spectra spectrophotometric method (MCR) that depends on using the mean centered ratio spectra in two successive steps that eliminates the derivative steps and therefore the signal to noise ratio is enhanced. The developed MCR method has been successfully applied for determination of MET, DF and MEH in different laboratory prepared mixtures and in tablets. Method (II) is the partial least square (PLS) multivariate calibration method that has been optimized for determination of MET, DF and MEH in Dimetrol ® tablets and by updating the developed model, it has been successfully used for prediction of binary mixtures of DF and Metronidazole Benzoate ester (METB) in Dimetrol ® suspension with good accuracy and precision without reconstruction of the calibration set. CONCLUSION The developed methods have been validated; accuracy, precision and specificity were found to be within the acceptable limits. Moreover results obtained by the suggested methods showed no significant difference when compared with those obtained by reported methods. GRAPHICAL