Spirapril (SCH 33844) hydrochloride is a potent燼ngiotensin converting enzyme (ACE)爄nhibitor with antihypertensive activity. Spirapril competitively binds to ACE and prevents the conversion of angiotensin I to angiotensin II. Spirapril is an orally active prodrug of Spiraprilat and can be used for the research of hypertension, congestive heart failure