Preparation and in-vitro evaluation of floating microspheres of gabapentin

Gabapentin dosage form could be designed to release the drug in the stomach at a rate providing the maximum amount of drug absorbable by the upper intestinal segment using the multiple- unit floating system to increase the gastric residence time (GRT) of the dosage forms. The floating microspheres were prepared by the solvent evaporation method using polymers ethyl cellulose and cellulose acetate. The microspheres were characterized for their particle size, shape, percentage yield, drug entrapment, buoyancy ratio, drug- polymer interaction and in-vitro drug release kinetics.  In addition, effects of the polymer type, polymer: drug ratio, solvent system compositions and temperature on the microspheres characteristics were studied. Investigations using optical microscope revealed spherical shape microspheres, with a size range at (45-1050µm), as well as high yield (99%), high drug entrapment (98%), high buoyancy ratio (≥95) and no drug-polymer interaction. A modified release rate (reach ten hours) was obtained.