TREATING AGENT FOR CEREBROVASCULAR DEMENTIA

PROBLEM TO BE SOLVED: To obtain a sustained-release treating agent for cerebrovascular dementia containing an oligopeptide having TRH activity. SOLUTION: This agent contains an oligopeptide having TRH activity, e.g. a compound of the formula (X is a 4- to 6-membered heterocycle; Y is imidazol-4-yl, 4-hydroxyphenyl or isopropyl; R and R are each H or a lower alkyl; R is H or a substitutable alkyl; Z is methylene or S) and releases the oligopeptide sustainably. The oligopeptide is preferably formulated into a buried formulation in which the oligopeptide is dispersed in a high molecular matrix, or an injection containing microspheres or microcapsules of the material obtained by crushing the buried formulation or of the oligopeptide itself. The quantity of TRH is 0.001-90% (w/w), preferably 0.01-70% (w/w) as the concentration in an inner water layer. A single dose for an adult is 0.35-35mg (0.007-0.7mg/ kg-body weight) in the case where the sustained-release agent is administered for a week in a basic administration.