Gemopatrilat is a vasopeptidase inhibitor, that was found to inhibit plasma and renal angiotensin converting enzyme (ACE), as well as renal neutral endopeptidase (NEP). Gemopatrilat is rapidly absorbed, and causes inhibition of circulating and renal ACE and renal NEP after a single oral dose for up to 48 hours in rats. Potentially, this is because the free sulfhydryl group of gemopatrilat forms reversible disulfide linkages with plasma and tissue proteins and is thus eliminated from the body at a very slow rate. Similar metabolism of the compound was found in rat, dog, and human. Gemopatrilat was evaluated for its potential in treatment of antihypertensive activity in hypertension (independent of age, renin and salt status or ethnic origin), as well as its potential as a new therapeutic modality for the treatment of congestive heart failure. The drug was never marketed. A phase II study for treatment of hypertension and heart failure has been discontinued.

Elisartan (HN 65021) is a selective, orally active, nonpeptide angiotensin II (AT1) antagonist. It antagonizes angiotensin receptor-mediated vasoconstriction. Elisartan was being assessed for the treatment of hypertension.

Guabenxan was developed as an oral antihypertensive drug.

Ripisartan (UP-269-6) is a specific nonpeptide angiotensin II receptor antagonist. Oral administration of ripisartan in rats and dogs resulted in a dose-dependent and long-lasting inhibition of the angiotensin II-induced pressor response. It did not show agonistic properties in animals. In vitro, ripisartan was found to bind selectively to AT1 receptors. In humans, it showed high biliary excretion and reabsorption. Canine studies have suggested it might have cardioprotective properties after acute ischemia-reperfusion.

Cromakalim is an ATP-sensitive potassium (KATP) channel opener, which was studied for the treatment of gastric ulcer, hypertension and preventing a cardiomyopathy. But the development of this drug was discontinued due to heart lesions found in monkey chronic toxicity studies.

Utibapril (FPL 63547) is an ester prodrug of a novel thiadiazoline ACE inhibitor. Utibapril was undergoing phase II clinical studies in the United Kingdom for the treatment of heart failure and hypertension. Utibapril is an angiotensin-converting enzyme (ACE) inhibitor with a proposed tissue-specific inhibitory profile. This implies that at a certain dose, utibapril should be able to inhibit tissue ACE activity without affecting plasma ACE.

Pinokalant is the isoquinoline derivative. It is a broad-spectrum cation channel blocker which inhibits store-operated cation channels in human endothelial cells, mast cells, HL60 cells and in primary cultures of cortical and hippocampal neurons. Pinokalant inhibits voltage-operated calcium channels of the L- and N-subtypes in primary cultures of cortical neurons and shows some antagonism on the NMDA- and AMPA glutamate receptor subtypes. Pinokalant also acts as an antagonist at the delayed rectifier K+ channel in PC12 cells and cortical neurons. Pinokalant reduced in vivo lesion size as well as post mortem infarct size derived from 2,3,5-triphenyltetrazolium chloride-stained brain slices 24 hr after middle cerebral artery occlusion. Pinokalant has been evaluated as a potential neuroprotectant in rodent models of stroke.

Pincainide is a new beta-amino anilide with local anesthetic properties. It has been shown to be 3 times more potent than lidocaine as a local anaesthetic on desheathed frog sciatic nerve. It was found to be effective against arrhythmias induced in guinea-pigs by ouabain infusion or by administration of adrenaline and chloroform. Pincainide not only inhibited the influx of Ca 2+ and increased 45Ca efflux, thus reducing the contractile responses induced in rat aorta by noradrenaline and high K +, but it also inhibited other effects related to the noradrenaline-induced release of intracellular Ca 2+ stores. Further studies, however, must be performed in experimental models of arrhythmias before the effectiveness of pincainide as an antiarrhythmic drug can be established.

Clofilium is a quaternary ammonium compound that acts as potassium channel blocker. Clofilium is a class III agent. Clofilium increases atrial and ventricular effective refractory period without changing conduction time and, despite no apparent change in premature ventricular complex frequency, it can abolish the ability to induce ventricular tachycardia by programmed stimulation and is also well tolerated.