Effect Of Chemical Composition On Release Behavior And Morphology Of Polyurethane Microspheres Prepared By Solvent Evaporation Method

Polyurethane micro spheres have been synthesized by solvent evaporation technique with castor oil, Polycaprolacton (PCL), Hexamethylen diisocyanate (HMDI) and Ethyl diamine (ED) as carriers for controlled drug delivery systems. Release behavior of micro spheres has been investigated using Bromocresol purple die. Fourier transmission infrared (FTIR), Scanning Electron Microscope (SEM), Optical microscope, dissolution instrument and UV spectrophotometer were used to investigate the polymerization process, surface morphology, particle size, rate of release and calibration curve respectively. Results showed that urethane bonds were formed at 3300-3400cm-1 and 1650-1700 cm-1. SEM micrographs showed surface irregularities as a result of solvent evaporation. Particle sizes were higher for castor oil/HMDI rather than PCL/HMDI microbe ads and in both cases, particle size and Bromocresol purple die release increased with rising NCO/OH ratio.