Q-Absorbance Ratio, Derivative Spectrophotometric and H-Point Standard Addition Methods for Simultaneous Determination of Pridinol Mesylate, and Diclofenac Sodium in Pharmaceutical Formulation.

Abstract

Three methods for simultaneous estimation of diclofenac sodium and pridinol mesylate have been developed. First method is the application of the Q-analysis (absorbance ratio) method, the wavelengths selected were 265nm (isosbestic point) and 285nm (λ max of diclofenac sodium) with 258nm (λ max of pridinol mesylate). The linearity ranges for diclofenac sodium and pridinol mesylate were 8-64 μg/ml and 14-56 μg/ml, respectively. The second technique is based on the second derivative spectrophotometric method at zero crossing wavelengths. The linearity ranges for diclofenac sodium and pridinol mesylate were (4.0-40.0) μg/ml and (4.0-30.0) μg/ml, respectively. The third method is the H-Point Standard addition method (HPSAM) depending upon the zero and second-order derivative signals for diclofenac sodium and pridinol mesylate were applied pairs of wavelengths, 250.37and 266.34 nm; with 224.18 and 235.10 nm, respectively. The accuracy of the methods was assessed by recovery studies and was found to be 100.01 ± 0.63 and 100.64 ± 0.36 for the qabsorbance ratio method, 100.78 ±0.221 and 101.98 ±0.11 for the second derivative zero-crossing method, respectively. While for H-Point Standard addition method are 98.0±1.71, and 100.4±0.545 for zero-order HPSAM , 99.25 ±0.753, and 100.12 ± 0.35 for second derivative HPSAM for diclofenac sodium and pridinol mesylate respectively Methods were confirmed according to the ICH guidelines; accuracy, precision, and repeatability were found to be within acceptable limits with no interferences. Finally, statistical comparisons between the proposed methods and the reported methods concerning to accuracy and precision show that no significant difference was found using Student's t-test, F-test, and one-way ANOVA.