Two simple methods for the estimation of albendazole and its dosage forms using chloramine-T.

Two simple, rapid and reliable methods for the determination of albendazole are described. Both methods involve the use of chloramine-T as the oxidimetric reagent. In the titrimetric method, a known excess of chloramine-T is added to an acidified solution of sample, and after a specified time, the residual oxidant is determined iodometrically. Spectrophotometric procedure also involves the addition of a measured excess of chloramine-T in buffer medium of pH 2.70+/-0.1 and after the reaction is ensured to be complete, the surplus oxidant is determined by a well established colour reaction involving metol and primary arylamine that results in charge-transfer complex measurable at 520 nm. In both methods, the amount of chloramine-T corresponds to the drug content. Reaction conditions were examined and optimised. Titrimetry is based on a 1:3 stoichiometric reaction between albendazole and chloramine-T and is applicable in the range of 1-15 mg. In spectrophotometry, the absorbance was found to decrease linearly with increasing concentration of albendazole, which is corroborated by the calculated correlation coefficient value of -0.9998. The system obeys Beer's law for 2.5-25 microg x ml(-1) of albendazole. The molar absorptivity and Sandell sensitivity were calculated to be 6.24 x 10(3) l mol(-1) cm(-1) and 42.54 ng cm(-2), respectively. The limits of detection and quantification were calculated to be 1.15 and 3.83 microg x ml(-1), respectively. The proposed methods were successfully applied to the determination of albendazole in commercially available dosage forms. The reliability of the assays was established by parallel determination by the official method and recovery studies.