Enhancement of itraconazole solubility and release by hot-melt extrusion with Soluplus®

Formulation of poorly water-soluble drugs is a significant challenge in the development of oral solid dosage forms. The objective was to investigate the effect of hot-melt extrusion process and formulation variables on the solid state, solubility and release of an ionizable poorly soluble drug, itraconazole (ITZ). Amorphous solid dispersions (ASD) were prepared by hot-melt extrusion and characterized by differential scanning calorimetry, x-ray diffractometry, FTIR spectroscopy and drug release. ITZ with the amphiphilic polymer carrier, Soluplus® resulted in molecular dispersions and improved drug solubility. The release of ITZ increased with increasing Soluplus® amount. Supersaturation was maintained for >24 h due to molecular dispersion of the drug in the carrier and the subsequent solubilization effect of the carrier. A lower supersaturation was obtained at processing temperatures (130 °C) below the drug melting point. The drug release was relatively slow, but complete within 6-8 h from large 5 mm extrudates and increased significantly by milling the extrudates and was nearly independent of particle size below 425 μm. In conclusion, the ASD led to solubility and release enhancement of the poorly water-soluble drug ITZ.