Abstract: 
The main aim of the study was to develop a stable gastroretentive In situ gel of Rivastigmine tartrate for Geriatric patients in the treatment of Alzheimer’s disease. Rivastigmine tartrate oral In situ gel was formulated by pH-triggered ionic gelation using various gelling polymers such as Sodium alginate, Gellan gum and Iota carrageenan along with HPMC K4M as release retardant. Prepared formulations were evaluated for Physical appearance, Pourability, pH, viscosity, In vitro gelation study, In vitro buoyancy study, Density, Gel strength, Percentage water uptake, Drug content and In vitro drug release. All the parameters showed differences based on the combination and concentration of polymers used. The pH and drug content of the formulations ranged from 6.94 – 7.39 and 98.04 – 99.83 % respectively. All the formulations showed floating lag time of less than 2 minutes and the duration of floating was greater than 12 hours. In vitro drug release study showed that only the Formulations F9 and F10 released 99.91 % and 91.11% of drug respectively at the end of 12 hours, while the other formulations showed more than 90% of drug release even before the period of 12 hours. In vitro release kinetic study of the optimized formulation F9 showed that the formulation followed Zero-order kinetics and Non-Fickian diffusion mechanism. The stability studies indicated that the optimized formulation F9 remained stable at the end of 3 months. The formulated gastroretentive In situ gel prolonged the gastric residence time resulting in controlled delivery of the drug.

Keywords: In Situ Gel, Floating, Gastroretentive, Oral, Liquid, Rivastigmine Tartrate, Gelling Polymers, Alzheimer’s Disease.