Titrimetric and Spectrophotometric Assay of Diethylcarbamazine Citrate in Pharmaceuticals Using N-bromosuccinimide

Background: Diethylcarbamazine citrate (DEC) is the drug of choice for the treatment of lymphatic filariasis, a disease which affects people in the tropical areas of the world. Mass treatment with DEC is recommended for control of lymphatic filariasis and in this connection, there is a need for an assay which could be used for the purpose of medication control. Objective: The present study is aimed at developing titrimetric and spectrophotometric methods for the determination of DEC in bulk as well as in dosage forms, using N-bromosuccinimide (NBS). Materials and Methods: In both methods, DEC is treated with a measured excess of standard NBS in HCl medium and after a standing time of 15 min, the residual NBS is determined either by titrimetry (iodometrically) or by spectrophotometry by reacting it with a fixed concentration of tropaeolin 000 followed by the measurement of the dye colour at 490 nm. The amount of NBS reacted is related to the amount/concentration of DEC, which serves as basis of assyas. Results: The experimental variables affecting the assays were carefully studied and optimized. Titrimetry is applicable over 3-18 mg range and the reaction follows a 1:1 ratio (DEC:NBS). In spectrophotometry, Beer's law is obeyed over the concentration range of 15-120 μg mLG1 with a molar extinction coefficient of 1.65×103 L molG1 cmG1. The calculated limits detection (LOD) and quantification (LOQ) are found to be 0.44 and 1.33 μg mLG1, respectively. Analysis of pure drug solution at three levels by the proposed methods had intra-day and inter-day coefficient of variation of <3% and the corresponding bias results were <2%. The methods were also validated for robustness, ruggedness and selectivity. Conclusion: The methods were successfully applied to the determination of DEC in tablets and syrup and the results compared well with the label claim and those obtained by the reference method. The study demonstrated the use of NBS and tropaeolin 000 as reagents in the titrimetric and spectrophotometric assay of DEC in pharmaceuticals.