To obtain a new platelet aggregation inhibitor useful for prevention and treatment of cerebral embolism, chronic arterial obstruction, etc., by using a specific heterocyclic derivative containing oxygen, its salt or its solvated or hydrated derivative as an active ingredient.
This platelet aggregation inhibitor includes a heterocyclic derivative containing oxygen of formula I [R1 is a group of formula II or III (R4 is a 1-20C alkyl, a 3-8C cyclolakly, etc.), etc.; R2 is a 1-6C alkyl; R3 is H or a group of formula IV (R5 is a 1-10C alkyl); A is a 1-3C alkylene], its salt or its solvated or hydrated derivative as an active ingredient. The compound of formula I is preferably (3S)-3-((S)-4-methyl-2- phenylsulfonylaminovalerylamino)-2-tetrahydrofuranol, etc. A clinical daily dose for an adult is preferably 0.1-1,000mg in terms of the compound of formula I in the case of an oral administration. The daily dose for the adult is preferably 0.01-100mg in terms of the compound of formula I when using as a parenteral injection.
SAITO KENICHI
ANDO RYOICHI
