Formulation and in vitro characterization of lansoprazole floating gastroretentive microspheres by modified non aqueous solvent evaporation method
By K.R. Vinod, A. Padma Sri, David Banji, S. Anbazhagan, Santhosh Vasa, S. Sandhya
One of the most feasible approaches for achieving a prolonged and predictable drug delivery profiles in the GIT is to control the gastric residence time (GRT) using gastroretentive dosage forms. The aim of the present study is to prepare the floating microspheres of lansoprazole and sustain the drug release for longer time to over come the short half life of the drug. Floating microspheres with four different ratios of polymer and drug were formulated by modified non-aqueous solvent evaporation method and in vitro evaluations were performed. The drug polymer dispersions were pressurized under CO2 gas, which upon release of the pressure cavities formed on the polymeric surface, which helps the microspheres to remain buoyant for prolonged time. Drug: polymer 1:4 ratio showed the %buoyancy 98.4%.It was observed that as the polymer concentration increases the buoyancy of microspheres also extended proportionally. SEM studies of microspheres showed good topology and the size was 280 μ. The cumulative % drug release in simulated gastric fluids after 10 hours was 82.0%-94.80%. Model fitting analysis revealed the release pattern was following Higuchi model for all formulations by obtaining maximum R2 value.
Key words: Lansoprazole, Hydroxypropylmethylcellulose, Ethylcellulose, Floating microspheres, kinetic assessment.