1. A pharmaceutical composition comprising: (1) a suvorexant or a pharmaceutically acceptable salt thereof； (2) a concentration increasing polymer, wherein the polymer increases the bioavailability of a suvorexant and is water soluble or dispersible in the form of. 2. The pharmaceutical composition of claim 1, wherein the concentration enhancing polymer is selected from the group consisting of ionizable cellulosic polymers, non-ionizable cellulosic polymers and vinyl polymers and copolymers having substituents selected from the group consisting of hydroxy, alkyl, acyloxy and cyclic amide. 3. The pharmaceutical composition of claim 2, wherein the concentration enhancing polymer is selected from the group consisting of hydroxypropyl methyl cellulose acetate succinate (HPMCAS), hydroxypropyl methyl cellulose phthalate (HPMCP), cellulose acetate phthalate (CAP), cellulose acetate trimellate (CAT) methyl cellulose phthalate, hydroxypropyl cellulose acetate phthalate, cellulose acetate terephthalate, cellulose acetate isophthalate, copolymers of polyvinylpyrrolidinone and polyvinylpyrrolidinone-polyvinyl acetate. 4. The pharmaceutical composition of claim 3, wherein the concentration enhancing polymer is selected from the group consisting of hydroxypropyl methyl cellulose acetate succinate (HPMCAS) and hydroxypropyl methyl cellulose phthalate (HPMCP). The pharmaceutical composition of claim 4, wherein the concentration enhancing polymer is hydroxypropyl methylcellulose acetate succinate (HPMCAS). The pharmaceutical composition of claim 2, wherein the concentration enhancing polymer is selected from the group consisting of vinyl polymers and copolymers having substituents selected from the group consisting of hydroxy, alkyl, acyloxy, and cyclic amide. The pharmaceutical composition according to claim 6,1. Фармацевтическая композиция, содержащая:(1) суворексант или его фармацевтически приемлемую соль；(2) полимер, повышающий концентрацию, где полимер повышает биодоступность
