A tolvaptan solid dispersion and its preparation method are disclosed. Thesoliddispersion comprises tolvaptan and crosslinked polyvinylprrolidone, at aweight ratioof 1:0.05-20, preferably 1:0.1-10, more preferably 2:1. The solid dispersioncan alsocomprise water-soluble polymer, such aspolyvinylprrolidone,hydroxypropylcellulose,hydroxyethylcellulose or methylcellulose. The weight ratio of tolvaptan :crosslinkedpolyvinylprrolidone : water-soluble polymers preferably is 2:1:0.1. The soliddispersion exhibits good thermodynamic stability and solubility. Thepharmaceuticalcomposition thereof has improved release rate and bioavailability.
