Design and Development of Drug Loaded Microsphere by Utilizing Emulsion Solvent Evaporation Method

Abstract

The aim of this study was to formulate and evaluate microencapsulated controlled release preparations of a highly water soluble drug, Indinavir sulphate(IDV), using polymers Ethyl cellulose(EC) and combination of EC and PVP as the retardant material. Microspheres were prepared by emulsion solvent evaporation method using an ethanol, dichloromethane and liquid paraffin system. Span 80 was used as the droplet stabilizer and n-hexane was added to harden the microspheres. The prepared microspheres were characterized for their micromeritic properties and drug loading, as well by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), X-Ray Powder Diffractometry (X-RD) and Scanning Electron Microscopy (SEM). The in vitro release studies were performed in distilled water. The prepared microspheres were white, free flowing and spherical in shape. The drug-loaded microspheres showed 69 % - 97% of entrapment and release was extended upto 2.5 to 7h. The infrared spectra and differential scanning calorimetry thermographs showed stable character of Indinavir sulphate in the drug-loaded microspheres and revealed the absence of drug- polymer interactions. X-ray diffraction patterns showed that there was decrease in crystallinity of the drug. Scanning electron microscopy study revealed that the microspheres were spherical and porous in nature. The best-fit release kinetics was achieved with Higuchi plot followed by Zero order and First order Kinetics. The release of Indinavir sulphate was influenced by the drug to polymer ratio and particle size and was found to be diffusion controlled.