The present study was focused to develop floating microspheres of Lamivudine in order to achieve an extended retention in the upper gastrointestinal tract, which may result in enhanced absorption and thereby improved bioavailability. The present study involves preparation and evaluation of floating microspheres using Lamivudine as a model drug for prolongation of the gastric retention time. As Lamivudine is mainly absorbed from stomach, thus using floating microspheres as a mode of drug delivery helps in increasing its residence time and hence increasing the bioavailability of drug. The microspheres were prepared by the Ionic gelation method. The average diameter and surface morphology of the prepared microspheres were characterized by optical microscope and scanning electron microscopic methods respectively. The prepared microspheres were evaluated for particle size, micromeritic study, drug entrapment efficiency, in vitro buoyancy, swelling index and in vitro release. The effect of various formulation variables on the size and drug release was also investigated. All the formulated microspheres were found to possess good flow properties. Scanning electron microscopy confirmed spherical structure of the prepared microspheres. The best formulation F3 drug release kinetics were evaluated using Zero order, First order, Higuchi model, Korsmeyer - Peppas model. After the interpretation of data that was based on the value of a resulting regression coefficient, it was observed that the Korsmeyer- Peppas model has a highest regression coefficient values indicating that the drug release was based on the erosion of polymeric chain matrix system

Lamuvudine, Floating microspheres, Gum acacia, Zero order, First order, Higuchi model, Korsmeyer-Peppas model

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