ro-42-5892 and zankiren-hydrochloride

The renin-angiotensin system (RAS) functions as a primary regulator in the short-term and long-term control of blood pressure. Pharmacologic inhibition of the RAS with angiotensin-converting enzyme (ACE) inhibition is effective for treating systemic hypertension and congestive heart failure. As a more specific therapy, the development of renin inhibitors has evolved through various approaches: specific renin antibodies, peptides developed from prosegments of renin precursor, oligopeptides related to pepstatin a universal inhibitor of aspartyl proteinase enzyme, and analogs of angiotensinogen (the renin substrate). Angiotensinogen analogs are promising as therapeutic agents because of high potency, metabolic stability, and good oral bioavailability. Ongoing research is directed towards the application of renin inhibition, the treatment of various cardiovascular disorders, and as a biological probe for understanding the role of the RAS in control of blood pressure and blood volume.

Topics: Amides; Angiotensin-Converting Enzyme Inhibitors; Heart Failure; Humans; Hypertension; Imidazoles; Morpholines; Pharmacology, Clinical; Piperazines; Renin; Renin-Angiotensin System; Thiazoles

Aliskiren is a new renin inhibitor of a novel structural class that has recently been shown to be efficacious in hypertensive patients after once-daily oral dosing. We report the results of animal experiments performed in marmosets and rats in order to characterize aliskiren before its recent investigation in humans.. The effects of aliskiren were investigated in sodium-depleted marmosets (oral dosing) and in spontaneously hypertensive rats (dosing via subcutaneous osmotic minipumps). Blood pressure (BP) and heart rate were measured by radiotelemetry.. In sodium-depleted marmosets, single oral doses of aliskiren (1-30 mg/kg) dose-dependently lowered BP. At a dose of 3 mg/kg, peak effects were observed 1 h after dosing (-30 +/- 4 mmHg, n = 6) and the response persisted for more than 12 h. A single oral dose of 3 mg/kg aliskiren was more effective than the same dose of either remikiren or zankiren, two orally active renin inhibitors previously tested in humans. Aliskiren (10 mg/kg) was at least as effective as equal doses of the AT1-receptor blocker valsartan or the angiotensin-converting enzyme inhibitor benazepril. In spontaneously hypertensive rats, aliskiren dose-dependently (10-100 mg/kg per day) decreased BP. Aliskiren also potentiated the antihypertensive effects of low doses of valsartan or benazeprilat (1 or 3 mg/kg per day).. Aliskiren is an orally effective, long-lasting renin inhibitor that shows antihypertensive efficacy in animals superior to previous renin inhibitors and at least equivalent to angiotensin-converting enzyme inhibitors and AT1-receptor blockers. Aliskiren may therefore represent an effective, novel approach to the treatment of hypertension and related disorders, alone or in combination with other antihypertensive agents.

Topics: Administration, Oral; Amides; Angiotensin II Type 1 Receptor Blockers; Angiotensin-Converting Enzyme Inhibitors; Animals; Benzazepines; Blood Pressure; Callithrix; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Drug Interactions; Female; Fumarates; Heart Rate; Imidazoles; Injections, Intravenous; Male; Piperazines; Rats; Rats, Inbred SHR; Renin; Telemetry; Tetrazoles; Thiazoles; Valine; Valsartan