Enhancement of dissolution and bioavailability of piroxicam in solid dispersion systems

Solid dispersion systems of water-insoluble piroxicam in polyethylene glyco l (PEG) 4000 and in urea were prepared by fusion and solvent methods and we re characterized in this study. The in vitro dissolution studies showed tha t the dispersion systems containing piroxicam and PEG4000 or urea gave fast er dissolution than the corresponding simple mixtures. The differential sca nning calorimetry (DSC) study indicated that the piroxicam-PEG system prepa red by the fusion method is a solid dispersion, while the piroxicam-urea sy stem prepared by the solvent method is likely to be a solid solution of pir oxicam in urea. The storage testings showed that all dispersions were stabl e, except that uptake of water during storage may occur in the PEG system. A single-dose study with rabbits showed that the dispersion systems provide d statistically significant to a higher extent and rate of bioavailability than the corresponding physical mixture (p < 0.05).