Effect of Radiation Sterilization on the Physicochemical Properties and Microbial Load of Amoxicillin Tri-Hydrate Powder

Amoxicillin tri-hydrate powder was irradiated at different doses of gamma radiation, and the subsequent changes in terms of physicochemical properties and potency were evaluated. A dose of 0.5 Mrad was found to be enough to sterilize the powder, which had an initial bacterial count of 6.2 x 10 1 cfu/ml. The original snow-white colour of the powder changed to light brown upon irradiation doses over 2.5 Mrad. The pH decreased upon increase of radiation dose. The iodometric titration assay showed only a little variation in potency (about 1-4%) of the test materials after irradiation. High performance liquid chromatography (HPLC) analysis of irradiated amoxicillin tri-hydrate powder showed no marked loss of potency by irradiation even up at a dose of 10.0 Mrad. No degradation product and extra peak was found at this high dose. The results indicated that dried powder of amoxicillin tri-hydrate is stable after sterilization by irradiation. Keywords: Amoxicillin tri-hydrate, Irradiation, Radiosterilization DOI: http://dx.doi.org/10.3329/bjm.v23i2.886 Bangladesh J Microbiol, Volume 23, Number 2, December 2006, pp 165-167