Original Articles
Rashmi Dahima
Abstract
The advantages of controlled release products are well known in the pharmaceutical field and include the ability to maintain a desired blood level of a medicament over a comparatively longer period of time. While many oral controlled and sustained release formulations are already known, certain drugs that are relatively insoluble in water and which further have relatively high dose requirements (based on weight) present formulation difficulties which render them unsuitable for inclusion in sustained release formulations. Nitazoxanide, a high dose, water insoluble antiprotozoal drug, is commercially available as immediate release dosage form. There is still a need in the art of formulation of sustained release dosage forms to formulate insoluble antiprotozoal that have enhanced bioavailability and provide suitable release profiles of the drug. The study was undertaken with the aim to formulate and evaluate Nitazoxanide sustained release granules using HPMC grades of polymer as retarding agent. These granules were coated with beeswax/cetyl alcohol. The in vitro dissolution studies were carried out with granules equal to 500 mg drug, using USP apparatus type I (Basket) at 100 rpm. Using 750 ml of 0.1N hydrochloric acid for the first 2 hours followed by 1000 ml of phosphate buffer pH 6.8 from 3 to 24 hours, medium maintained at 37°C ± 0.5°C. A sustained release profile was shown up to 24 hrs. The slope value of more than 0.7, however, appears to indicate a coupling of diffusion and erosion mechanisms – so called anomalous diffusion.