Lisinopril is a potent, competitive inhibitor of angiotensin-converting enzyme (ACE). Lisinopril is marketed under the brand name ZESTRIL. ZESTRIL is indicated for the treatment of hypertension. It may be used alone as initial therapy or concomitantly with other classes of antihypertensive agents. It is also indicated as adjunctive therapy in the management of heart failure in patients who are not responding adequately to diuretics and digitalis. Lisinopril inhibits angiotensin-converting enzyme (ACE) in human subjects and animals. ACE is a peptidyl dipeptidase that catalyzes the conversion of angiotensin I to the vasoconstrictor substance, angiotensin II. Angiotensin II also stimulates aldosterone secretion by the adrenal cortex. The beneficial effects of lisinopril in hypertension and heart failure appear to result primarily from suppression of the renin-angiotensin-aldosterone system. Inhibition of ACE results in decreased plasma angiotensin II which leads to decreased vasopressor activity and to decreased aldosterone secretion. While the mechanism through which ZESTRIL lowers blood pressure is believed to be primarily suppression of the renin-angiotensin-aldosterone system, ZESTRIL is antihypertensive even in patients with low-renin hypertension.

(R)-Lisinopril Sodium Salt is the R,S,S-Isomer of Lisinopril. Lisinopril is a potent inhibitor of angiotensin-converting enzyme (ACE). Lisinopril prevents the conversion of angiotensin I to angiotensin II, which acts as a potent vasoconstrictor and also signals the release of aldosterone, which modulates sodium absorption. ACE inhibition has the net result of vasodilation and increased sodium and water excretion. Lisinopril, (2S)-1-[(2S)-6-amino-2-[[(1S)-1-carboxy-3-phenylpropyl]amino] hexanoyl]pyrrole-2-carboxylic acid is an angiotensin-converting enzyme (ACE) inhibitor, used for the treatment of hypertension, heartfailure andacutemyocardial infarction. The RSS isomer of lisinopril ((2S)-1-[(2S)-6-amino-2-[[(1R)-1-carboxy- 3-phenylpropyl]amino]hexanoyl]pyrrole-2-carboxylic acid) is an impurity (impurity E) resulting from the synthesis of lisinopril. The impurity profile of a drug substance is critical to its safety assessment and is important for monitoring the manufacturing process.