Prophylactic and/or therapeutic agent for mild cognitive impairment

Abstract

Provided is a prophylactic and/or therapeutic drug for mild cognitive impairment, which can improve interstitial flow in cerebral blood vessel and the like to achieve sufficient clearance of harmful proteins accumulated in the brain. The prophylactic and/or therapeutic drug includes 6-[4-(1-cyclohexyl-1H-tetrazole-5-yl)butoxy]3,4-dihydrocarbostyril or a salt thereof as an active ingredient. The prophylactic and/or therapeutic drug can improve a flow of interstitial fluid around blood vessels in a drainage pathway to excrete harmful proteins. The prophylactic and/or therapeutic drug for mild cognitive impairment may take the form of a pharmaceutical product for oral administration, a liquid pharmaceutical product for oral administration, or an injectable preparation. The prophylactic and/or therapeutic drug for mild cognitive impairment can be used for the prevention and/or treatment of cerebral amyloid angiopathy, and can also be used for improvement of Lewy body disease, Down's syndrome, or macular degeneration.

1 . A prophylactic and/or therapeutic agent for mild cognitive impairment, the agent comprising, as an active ingredient, a carbostyril derivative expressed by general formula (1) or a salt thereof: 
       
         
           
           
               
               
           
         
         wherein A is a straight-chain alkylene group having a carbon number of 1 to 6, R is a cycloalkylaryl group having a carbon number of 3 to 8, and a bond between 3- and 4-positions of a carbostyril skeleton is a single bond or a double bond. 
       
     
     
         2 . The prophylactic and/or therapeutic agent for mild cognitive impairment of  claim 1 , wherein
 the carbostyril derivative expressed by general formula (1) is 6-[4-(1-cyclohexyl-1H-tetrazole-5-yl)butoxy]3,4-dihydrocarbostyril.   
     
     
         3 . The prophylactic and/or therapeutic agent for mild cognitive impairment of  claim 2 , wherein
 the agent is administered to a patient group having MMSE scores greater than or equal to 22 and less than or equal to 26.   
     
     
         4 . The prophylactic and/or therapeutic agent for mild cognitive impairment of  claim 2  or  3 , wherein
 powder of 6-[4-(1-cyclohexyl-1H-tetrazole-5-yl)butoxy]3,4-dihydrocarbostyril having an average particle size less than or equal to 4 μm is mixed as an active ingredient in a surfactant. 
 
     
     
         5 . An interstitial flow-improving agent, comprising, as an active ingredient, a carbostyril derivative expressed by general formula (1) or a salt thereof: 
       
         
           
           
               
               
           
         
         wherein A is a straight-chain alkylene group having a carbon number of 1 to 6, R is a cycloalkylaryl group having a carbon number of 3 to 8, and a bond between 3- and 4-positions of a carbostyril skeleton is a single bond or a double bond. 
       
     
     
         6 . The interstitial flow-improving agent of  claim 5 , wherein
 the carbostyril derivative expressed by general formula (1) is 6-[4-(1-cyclohexyl-1H-tetrazole-5-yl)butoxy]3,4-dihydrocarbostyril.   
     
     
         7 . The interstitial flow-improving agent of  claim 5  or  6 , wherein
 powder of 6-[4-(1-cyclohexyl-1H-tetrazole-5-yl)butoxy]3,4-dihydrocarbostyril having an average particle size less than or equal to 4 μm is mixed as an active ingredient in a surfactant.