Determination of flubendazole in pharmaceutical dosage forms by differential pulse polarography and UV spectroscopy.

A precise and accurate differential pulse polarographic method was developed for the determination of flubendazole in dosage forms without any prior extraction procedure of interference from the other stated ingredients. A UV spectroscopic procedure was also described and used as reference method. Analyses were generally performed at the 4 micrograms ml-1 flubendazole level. Flubendazole or its dosage forms were dissolved in 70% perchloric acid and diluted with a pH 2.6 sodium phosphate-citric acid buffer as polarographic supporting electrolyte or spectrophotometric solvent. The peak potential occurred at about -0.9 V (vs. Ag/AgCl reference electrode), depending on the pH of the assayed solution. The irreversible electrochemical reduction involved the transfer of two electrons. The UV absorption spectrum showed a sharp maximum at 237 nm with a specific extinction coefficient of 886. No advantage was found in the use of first and second-order derivative spectrophotometry.