RAPID AND ACCURATE METHOD FOR DETERMINATION OF NICLOSAMIDE RELEASED FROM MOLLUSCICIDAL FORMULATIONS

A rapid, simple, and reproducible method was developed for quantitativ e determination of niclosamide ethanolamine salt (NES) - the most wide ly used molluscicide against snail vectors of schistosomiasis - in bot h distilled and natural canal waters. The biocide is extracted complet ely from water samples by passing through Sep-Pak C18 cartridge and el uting the cartridge with methanol. The eluate is then analyzed directl y for NES by UV/vis spectrophotometry at 330 nm. This method was found sensitive enough to detect 0.1-5 ppm, and it is highly reproducible ( standard deviation, 0.006-0.012). The standard curve obeyed Beer's law . The method also successfully measured the release rate of NES from c ontrolled-release elastomeric formulations. The release study suggests that NES loading and certain rubber additives are not the key factors that govern the release of the biocide.