Formulation and Evaluation of Controlled Porosity Osmotic Drug Delivery System of Metoprolol Succinate

Controlled porosity osmotic tablet of metoprolol succinate prepared and evaluated in this study. Metoprolol succinate is very high soluble drug, so complete drug release obtained very fast. It is difficult to formulate osmotic tablet of Metoprolol succinate which gives drug release up to 24 hr at zero order. To get desired dissolution profile various formulation parameters like osmogen concentration, level of weight gain and level of pore former concentration were studied. Hypromellose was added as release retardant to reduce its dissolution rate and get drug release up to 24 hr at zero order. As concentration of release retardant increases, dissolution rate decreases. Final optimized formulation with hypromellose was studied for effect of pH of dissolution media, agitation intensity and osmotic pressure of dissolution media. There is no effect of above variables on dissolution confirms that prepared metoprolol succinate tablet gives drug release with osmotic mechanism. Final optimized formulation complies with the USP criteria for the dissolution of metoprolol succinate extended release tablet. INTRODUCTION: Conventional drug delivery systems have little control over the drug release and so effective concentration at the target site can not be achieved. This kind of dosing pattern may result in unpredictable plasma concentrations. But oral controlled drug delivery dosage forms provide desired drug release pattern for longer period of time and so the rate and extent of drug absorption from oral controlled drug delivery formulations can be predicated. However, drug release from oral controlled release dosage forms may be affected by pH, GI motility and presence of food in the GI tract . But drug release from osmotic drug delivery system is not affected by physiological factors. Controlled porosity osmotic tablet contains core tablet coated with semipermeable membrane which allows active agent to come outside through pores formed in situ. The controlled-porosity osmotic pump has been developed via incorporation of leachable water-soluble small molecules, such as sodium chloride, potassium chloride, urea, and sucrose etc. into major component of film coating material . These pore-forming agents are leached when contacted with an aqueous medium, and the pores are created on the surface to allow drug release. Plasticizer can also be used as pore forming agent. Plasticizer has been used to modify not only the mechanical properties but also the thermal property, water absorption behavior, and adhesive property of polymeric films . Correspondence to Author: