Development and Characterization of Rivastigmine Hydrogen Tartrate Elementary Osmotic Tablets

Background: The present study aims to develop an Elementary Osmotic tablet (EOP) of Rivastigmine Hydrogen Tartrate (RHT). EOP consists of a core tablet suitably coated with a polymeric solution, and an orifice drilled on one side of the tablet. Materials and Methods: The influence of core variables, including sodium chloride (osmogen) concentration and Polyvinyl Pyrrolidine K30 (PVP K30) concentration, have been investigated and optimized by factorial design. The effect of membrane (coating) variables, including polyethylene glycol 400 (PEG 400) amount and percent coating weight gain have been studied. The rivastigmine release of the optimized system has been investigated in various dissolution media, at different stirring rates, at variable pH, and variable osmotic pressure. Results: It was observed that PEG 400 incorporated in the coating membrane improved drug release. The sodium chloride had a profoundly positive influence, and PVP K30 had a negative influence on the rivastigmine release. The finding reveals that the core tablet containing sodium chloride (50 mg) and PVP K30 (2.5 mg) coated with the solution containing 20% PEG 400 and 5% weight gain was optimized. Conclusion: The developed EOP provides the RHT release for up to 24 hr with improved bioavailability. The results instigated a controlled release of rivastigmine.