Development and optimization of multi-unit solid dispersion systems of poorly water soluble drug

Glipizide (GPZ) and GPZ-HPC solid dispersion (SD) pellets were developed and characterized for drug release mechanisms from a multi-unit erosion matrix system for controlled release. Solid dispersion with HPC was prepared by coevaporation method and characterized by Fourier transform infra red spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), hot-stage microscopy (HSM), x-ray diffraction (XRD), stability studies. Release rate of GPZ from solid dispersion was measured by the rotating basket method (JP XII). FT-IR study indicated the presence of hydrogen bonding in solid dispersion. SEM confirms the amorphous form in solid dispersion. In DSC melting peak in solid dispersion shifted slightly to lower temperature with respect to drug alone indicated the conversion to amorphous form which was further proved in XRD. HSM have demonstrated the ability of melted HPC to dissolve the crystal of GPZ at increasing temperatures. The release rate of GPZ from solid dispersion granules was markedly larger than that from GPZ powder, and it was larger with a lower HPC molecular weight. The stability study showed that SD systems were not significantly different during six month of accelerating condition storage.