Validated Simultaneous Derivative Spectrophotometric Estimation of Diflunisal and Lignocaine in Bulk and Pharmaceutical Formulation

Abstract

Two simple, sensitive, accurate and precise spectrophotometric methods were developed and validated for the quantitative determination of Diflunisal (DIF) and Lignocaine (LIG) in bulk and pharmaceutical dosage form. Method A is based on the first-order derivative (D1), and Method B is based on the second-order derivative (D2) spectrophotometric method. In Method A, absorbance was measured at 224nm and 264nm being the zero crossing points for DIF and LIG, respectively. In Method B, absorbance was measured at 232nm and 273nm being the zero crossing points for DIF and LIG, respectively. For Method A, the two drugs obeyed Beer's law in the concentration range of 3-39µg/ml for DIF and 4-40 µg/ml for LIG with correlation coefficients 0.999 and 0.995, respectively. For Method B, the two drugs obeyed Beer’s law in the concentration range of 3-30µg/ml for DIF and 4-48µg/ml for LIG with correlation coefficients 0.998 and 0.996, respectively. Both methods can be used for routine analysis of these two drugs in their pharmaceutical dosage form. Results for analysis of both methods were tested and validated for various parameters according to ICH guidelines.  Keywords: Derivative, Diflunisal, Lignocaine, first order, second order