PYRIDAZINONE DERIVATIVE AND PDE INHIBITOR COMPRISING THE SAME AS ACTIVE INGREDIENT

摘要

PROBLEM TO BE SOLVED: To provide a novel pyridazinone derivative useful as a pharmaceutical product having a phosphodiesterase inhibitory activity. SOLUTION: A phosphodiesterase (PDE) inhibitor contains the pyridazinone derivative represented by formula (1) [wherein Heterocycle represents a benzoxazole ring or a benzothiazole ring], an optical isomer thereof, a pharmacologically acceptable salt thereof or a hydrate thereof as an active ingredient. COPYRIGHT: (C)2008,JPO&INPIT