Preparation and in Vitro Dissolution of Tolvaptan Solid Dispersion

OBJECTIVE To enhance the dissolution rate of tolvaptan which is a poorly water-soluble drug by solid dispersion. METHODS Solid dispersions of tolvaptan were prepared by solution evaporation method, with polyvinylpyrro- lidone(PVP) K29/32 as the matrix. The physical states of tolvaptan were investigated by differential scanning calorimetry(DSC) and X-ray powder diffraction analysis(XRPD). The solubility and dissolution rate of tolvaptan, solid dispersions and physical mixtures were also compared. RESULTS The DSC and XRPD spectrum of the solid dispersion showed that tolvaptan existed as amorphous form in solid dispersion. The dissolution of tolvaptan solid dispersions was much faster than that of tolvaptan and the physical mixtures. CONCLUSION PVP K29/32 solid dissolution containing tolvaptan has changed its dispersion form with higher dissolution.