Formulation and Evaluation of Silymarin Floating Drug Delivery System
A Gastroretentive floating controlled drug delivery system containing Silymarin was prepared in the form of tablets and evaluated for its processing parameters, in vitro release in 0.1 N HCl. Eight formulations were prepared by using rate controlling polymers such as HPMC K4M and Eudragit RS100, alkalizing agent sodium bicarbonate and solubilizing agent poly vinyl Pyrrolidone (PVP K30). Floating tablets were prepared by direct compression method. The preformulation studies and tablet evaluation tests were performed and results were within the limits. Tablets remained buoyant over 20 hours in the release medium and the amount of sodium bicarbonate found to be significant for not only to remaining buoyant without causing disintegration of the tablet. The different ratios of polymers 15% and 20% showed the significant difference in the drug release with increasing in the concentration of solubilizing agent PVP K30. All the formulations exhibited diffusion dominant drug release. Stability studies for all formulations were conducted for a period of 60 days at 4°±2°C, 27°±2°C and 45°±2°C respectively and the formulations showed no significant changes in physical appearance, drug content and in-vitro drug release even after 60 days.