Solid lipid dispersion of calcitriol with enhanced dissolution and stability

Solid dispersion of calcitriol with lipophilic surfactants and triglycerides was developed by melt-mixing method to modify the release and enhance stability of the drug. The solid dispersions were characterized by differential scanning calorimetry (DSC), hot stage polarized optical microscopy (HSPM), infrared spectroscopy (FTIR) and stability studies. The solid dispersion significantly enhanced the stability of calcitriol, which could be attributed to the high antioxidant activity of the solid lipid dispersion. The rapid dissolution rate from the solid dispersion was attributed to the amorphous or solid solution state of drug with improved specific surface area and wettability than the drug crystals. Therefore, solid dispersion of calcitriol with d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) offers a good approach to modify the release and enhance stability of calcitriol. The influence of lipophilic solid dispersion on drug bioavailability needs further investigation.