Studies on Flash Evaporation for Preparation of Porous Solid Dispersions Using Piroxicam as a Model Drug

An amalgamation of solid dispersion and capillarity has been attempted in present study for enhancement of dissolution rate of poorly soluble drugs. Flash evaporation technique was utilized for enhancement of the dissolution rate of piroxicam. One of the major problems with this drug is its very low solubility in biological fluids, which results in poor bioavailability after oral administration. An attempt was made to enhance the dissolution rate of piroxicam by converting it into porous solid dispersion by flash evaporation method using polyvinylpyrrolidone (PVP) 40,000 as a water-soluble carrier. The resulting solid dispersions were characterized by DSC, FTIR, and X-ray diffraction. In vitro dissolution study revealed significant improvement of dissolution profile of piroxicam. The release of drug from porous solid dispersions containing PVP was superior to those of marketed product, conventional nonporous solid dispersion prepared by solvent evaporation method and drug alone. The steep increase in dissolution rate of porous form is attributable to combined effect of solid dispersion and capillarity.