Spectrophotometric assay of diethylcarbamazine citrate in pharmaceuticals and spiked human urine by ion-pair reaction with Tropaeolin 000

Abstract

A simple, rapid and extractive spectrophotometric method is presented for the determination of diethylcarbamazine citrate (DEC) in bulk drug, dosage forms and spiked human urine. The method is based on the formation of orange ion-pair complex between basic DEC and the acidic dye: Tropaeolin 000 (TRN), in Clarks-Lubs buffer of pH 1.42. The formed complex was extracted into chloroform and the absorbance was measured at 490 nm. Effected of several experimental variables were investigated on complex formation and optimized. Beer’s law is obeyed over the concentration range, 2.0-70 µg mL^-1 (r =0.9995) with a molar absorptivity value of 5.207×10³L mol^-1 cm^-1. The limits of detection (LOD) and quantification (LOQ) were calculated to be 0.15 and 0.46 µg mL^-1, respectively. The composition of the ion-pair was found to be 1:1 (DEC:TRN) by Job’s method of continuous variations. The relative standard deviation (%RSD) values for intra-day and inter-day precision were less than 1.5% and the relative errors (%RE) values were better than 2.0%. The method was applied to the determination of DEC in tablets and suspension and the results agreed well with the label claim. The accuracy of the method was confirmed by recovery study via standard-addition procedure. Because, it is sensitive, the method was applied to spiked human urine with an excellent percent recovery of 96.38±1.64.