Formulation and in vitro evaluation of salbutamol sulphate floating microspheres

The objective of the present study was to develop once daily sustained release floating dosage form of salbutamol sulfate. The study involves the preparation of floating microspheres of salbutamol sulfate coated with Eudragit L100 using solvent evaporation method and its in vitro characterization. Three batches (F1, F2 & F3) of microspheres were prepared taking three drug: polymer ratios (1:1, 1:2 & 1:3). The entrapment efficiency was increased with the increment in polymer concentration. The microspheres remained buoyant in acidic medium containing surfactant for 8-12 hours in vitro. The mean particle size increased and the drug release rate decreased at higher polymer concentration. The surface morphology of microspheres characterized by SEM showed microspheres with smooth surface. The in vitro drug release studies were carried out for 12 hours both in 0.1N HCl (pH 1.2) and pH 6.8 buffers. The release studies showed the drug release was faster in intestinal pH as compared to gastric pH due to the polymer solubility in pH from 6