Consequences of formulation variables on physicochemical properties of indinavir sulfate microspheres

ABSTRACT

Indinavir sulfate with ethyl cellulose microspheres was successfully prepared by an oil-in-oil emulsion solvent evaporation technique using acetonitrile dichloromethane [11] and light liquid paraffin as primary and secondary oil phases respectively with span 80 as a droplet stabilizer. In present study the effect of formulation variable e.g., polymer to drug ratio, viscosity of ethyl cellulose, volume of light liquid paraffin and effect of processing temperature on yield, encapsulation efficiency, particle size and in vitro drug release characteristics of the Indinavir microspheres were investigated. The prepared microspheres were spherical with stable nature of drug within the formulations confirmed by Fourier transform infrared spectra. The mean sphere diameter and encapsulation efficiencies depended strongly on the drug to polymer ratio, viscosity of polymer, volume of processing medium and processing temperature. The release of indinavir sulfate was diffusion controlled and influenced by the drug to polymer ratio, viscosity of polymeric phase, volume of light liquid paraffin used and processing temperature condition