The present invention provides solid dispersions or solid dispersion pharmaceutical preparations containing a water-soluble polymeric substance(s) and a phenylalanine compound of the formula (1) or pharmaceutically acceptable salts thereof, wherein A represents the formula (2) and the like, B represent an alkoxy group and the like, E represents a hydrogen atom and the like, D represents a substituted phenyl group and the like, T, U and V represent a carbonyl group and the like, Arm represents a benzene ring and the like, R1 represents an alkyl group and the like, R2, R3, and R4 may be the same or different from one another and each represent a hydrogen atom, a substituted amino group and the like, and J and J′ represent a hydrogen atom and the like； production methods thereof； and solubilized pharmaceutical preparations containing a solubilizer(s) and the compound (I) or pharmaceutically acceptable salts thereof. According to the solid dispersion pharmaceutical preparations or solubilized pharmaceutical preparations, though they contain the phenylalanine compound of the formula (1) that is a poorly-soluble drug as an active ingredient, the pharmaceutical preparations having high solubility and oral absorbability can be obtained.
