Preparation and Evaluation of Sustained Release Tablet of Rifaximin by using Cross linked Sodium Alginate

Rifaximin treats traveler's diarrhea and irritable bowel syndrome by stopping the growth of the bacteria that cause diarrhea. Rifaximin treats hepatic encephalopathy by stopping the growth of bacteria that produce toxins and that may worsen liver disease. The short half life and high frequency of administration of drug makes it a suitable candidate for designing sustained drug delivery system. The aim of the present investigation was to develop a sustained release matrix tablet of Rifaximin using sodium alginate and cross linked sodium alginate and to evaluate the drug release kinetics. In order to achieve the required sustained release profile, the tablets were prepared by a wet granulation method. The formulated tablets were characterized for pre-compression and post-compression parameters and they were in the acceptable limits. The drug release data obtained after an in vitro dissolution study was fitted to various release kinetic models in order to evaluate the release mechanism and kinetics. The criterion for selecting the best fit model was linearity (coefficient of correlation). Drug release mechanism was found to follow a complex mixture of diffusion, swelling and erosion. The dosage form holds the potential to control the release rate of drug and extend the duration of action of a drug.