Development and evaluation of ethylcellulose floating microspheres loaded with ranitidine hydrochloride by novel solvent evaporation-matrix erosion method

Ranitidine hydrochloride loaded floating microspheres were prepared by novel solvent evaporation-matrix erosion method using ethylcellulose and polyethylene glycol (PEG) blend. PEG employed as pore forming agent to induce buoyancy. Formulated microspheres were evaluated for various physicochemical properties. Drug loading, entrapment and encapsulation of microspheres were 23-32, 86-96 and 75-86% (w/w), respectively. The average particle sizes were between 45 and 106 μm and reduced as % of PEG increases in the microspheres. Ethylcellulose microspheres prepared with 20-33.3% of PEG showed floating properties. Scanning electron microscopy revealed the presence of pores on the surface of floating microspheres due to matrix erosion, which are responsible for floating ability. Fourier-transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction studies indicated intact and amorphous nature of entrapped drug in the microspheres. The drug loaded microspheres could float 10 h and sustain the drug release over 4-6 h.