Abstract: 
A sustained release drug delivery system for acebutolol hydrochloride was designed to increase its residence time in the stomach without establishing contact with the mucosa. This was made possible through the preparation of microballoons by emulsion solvent diffusion-evaporation technique. The prepared microballoons were characterized for physical characteristics such as particle size, particle shape and surface morphology by scanning electron microscopy. Further, percentage yield determination, drug entrapment efficiency, in vitro buoyancy test, micromeritic investigations and in vitro drug release studies were carried out. The obtained microspheres were free flowing, spherical and displayed a particle size ranging from 52.37 to 67.5µm suitable for oral delivery. The drug entrapped in the hollow microspheres increased with the increase in eudragit RSPO content. Scanning electron microscopy and particle size analysis revealed differences in the formulations in respect to their appearance and size distribution. The Fourier Transform Infrared spectroscopy technique and Differential Scanning Calorimetry were carried out to rule out drug – excipients interactions. From the results obtained, it was concluded that there was no interaction between drug and the excipients. The formulation containing acebutolol: eudragit RSPO (1:3 and 1:4) exhibited higher percentage values for buoyancy time. The drug release was found to follow Higuchi kinetics with non-fickian diffusion mechanism, from all the four batches. These preliminary results indicate that acebutolol hydrochloride loaded microballoons could be effective in sustaining drug release for prolonged periods of time.

Keywords: Microballoons, Acebutolol Hydrochloride, Emulsion Solvent Diffusion-evaporation Method, Drug Entrapment Efficiency, Sustained Release.