Stability-Indicating UV-Spectrophotometric Assay of Diethylcarbamazine Citrate in Pharmaceuticals

Abstract

Diethylcarbamazine citrate (DEC) is a piperazine anthelmintic agent indicated for the treatment of individual patients with lymphatic filariasis. Two simple and sensitive UV-spectrophotometric techniques have been developed and validated for the determination of this drug in bulk parent substance and tablets, based on the measurement of the absorbance of DEC solution either in 0.1M HCl at 210 nm (method A) or in 0.1M H₂SO₄ at 209 nm (method B). Beer’s law was obeyed over the concentration ranges of 1.25 – 25.0 and 2.5 – 30.0 μg · mL^-1, for method Aand method B, respectively, and the corresponding molar absorptivity values were 2.02 × 10⁴ and 1.21 × 10⁴ L mol^-1 · cm^-1. The limits of detection (LOD) and quantification (LOQ) were, respectively, 0.26 and 0.78 μg · mL^-1 (method A), and 0.16 and 0.49 μg · mL^-1 (method B). These methods were assessed for intra-day and inter-day accuracy and precision, as well as robustness and ruggedness. Both methods were applied to one brand of tablets with percentage label claim of 101.7 and 100.8 for method A and method B, respectively, and the standard deviation was below 2%. In order to establish the stability-indicating ability of these methods, the drug was analyzed after subjecting it to acid and base hydrolysis, oxidation, heat and light stress conditions and the results indicated that the drug degraded extensively under both base- and oxidative-stress conditions, and remained intact under other stress conditions.