(1R,3S)-Benazepril hydrochloride, also known as Benazepril hydrochloride, is the active pharmaceutical ingredient (API) of the antihypertensive drug Benazepril. It is a potent, long-acting angiotensin-converting enzyme (ACE) inhibitor. The compound is a prodrug that is hydrolyzed in vivo to its active diacid metabolite, benazeprilat, which inhibits the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. This API is primarily used in the treatment of hypertension (high blood pressure) and congestive heart failure. It works by relaxing blood vessels, thereby reducing peripheral arterial resistance and lowering blood pressure without causing a compensatory increase in heart rate. Benazepril is often administered as a monotherapy or in combination with other antihypertensive agents like diuretics. The (1R,3S) stereochemistry is crucial for its pharmacological activity. As an API, it is formulated into various dosage forms, most commonly oral tablets. Handling requires standard safety precautions for pharmaceutical actives, including the use of personal protective equipment to avoid inhalation or skin contact.