Cetaben sodium, an antiatherosclerotic agent

Novel Phenotypic Outcomes Identified for a Public Collection of Approved Drugs from a Publicly Accessible Panel of Assays

Phenotypic assays have a proven track record for generating leads that become first-in-class therapies. Whole cell assays that inform on a phenotype or mechanism also possess great potential in drug repositioning studies by illuminating new activities for the existing pharmacopeia. The National Center for Advancing Translational Sciences (NCATS) pharmaceutical collection (NPC) is the largest reported collection of approved small molecule therapeutics that is available for screening in a high-throughput setting. Via a wide-ranging collaborative effort, this library was analyzed in the Open Innovation Drug Discovery (OIDD) phenotypic assay modules publicly offered by Lilly. The results of these tests are publically available online at www.ncats.nih.gov/expertise/preclinical/pd2 and via the PubChem Database (https://pubchem.ncbi.nlm.nih.gov/) (AID 1117321). Phenotypic outcomes for numerous drugs were confirmed, including sulfonylureas as insulin secretagogues and the anti-angiogenesis actions of multikinase inhibitors sorafenib, axitinib and pazopanib. Several novel outcomes were also noted including the Wnt potentiating activities of rotenone and the antifolate class of drugs, and the anti-angiogenic activity of cetaben.

ACAT inhibitors as antiatherosclerotic agents: compounds and mechanisms

Atherosclerosis is a major death cause in western industrialized countries. A diagnosing system, medical prevention, and treatment of atherosclerosis is not sufficient so far. A direct acting antiatherosclerotic agent is eagerly waited. ACAT inhibitor approach could provide such an agent. In the formation of atherosclerosis, cholesteryl esters, which are the lipids which accumulate in atheromatous plaques by an aid of macrophages and smooth muscle cells, forming foam cells, may play an important role. ACAT enzyme is responsible for the acylation of cholesterol to cholesteryl esters, a transformation which can be essential in not only cholesteryl esters accumulation at arterial walls but also the absorption of cholesterol in the intestine and the excretion of cholesterol in the liver. From these points, ACAT inhibitors might work against atherosclerosis in three different ways: first, cholesteryl ester accumulation inhibition at arterial walls could be a direct antiatherosclerotic effect; second, cholesterol absorption inhibition at the intestine; and third, cholesterol excretion acceleration at the liver, while the later two effects would result in a reduction of blood cholesterol level--a major risk factor of atherosclerosis. Taking account of this discussion, the ACAT inhibitors would be potent antiatherosclerotic agents. Medicinal research has been contributing full strength to produce an ultimate compound. These efforts should provide a drug which will be useful to patients.

Therapeutic potential of ACAT inhibitors as lipid lowering and anti-atherosclerotic agents

Hypercholesterolemia is one of the few independent risk factors definitively linked to increased morbidity and mortality due to myocardial infarction. One possible therapy of current interest is the prevention of the absorption of dietary cholesterol by inhibiting the enzyme, acyl-CoA: cholesterol acyltransferase (ACAT), which catalyses the intracellular formation of cholesterol esters. Evidence is now accumulating that suggests that ACAT inhibition may not only lower plasma cholesterol levels, but may also have a direct effect at the artery wall, where ACAT has been shown to be responsible for the accumulation of cholesterol esters in arterial lesions. Drago Sliskovic and Andrew White discuss the importance of ACAT in the lipid transport system and the consequences of its inhibition in a variety of tissues, with emphasis on both lipid-lowering and anti-atherosclerotic effects.

Atherosclerosis mouse model induced by a high-cholesterol diet supplemented with beta-aminopropionitrile: effects of various anti-atherosclerotic agents on the biochemical parameters

A mouse model of atherosclerosis was produced by feeding a 1.5% cholesterol diet with 0.4% beta-aminopropionitrile (BAPN) fumarate, a chemical lathyrogen, for 10 weeks, and the pharmacological sensitivity and specificity of this model were evaluated biochemically with various hypolipidemic drugs and calcium antagonists. Histological findings on this model showed typical angiolathyrism with foam cells in the media of the thoracic aorta. Uniform and marked accumulation of cholesterol, notably esterified cholesterol, in the aorta was observed, although it was much less in mice receiving a high-cholesterol diet or BAPN alone. The reduction in elastin contents in the aorta was a characteristic feature of this model. Clofibrate, cetaben and elastase tended to prevent the increase of cholesterol contents in the aorta, together with their significant hypocholesterolemic effects. Nifedipine, diltiazem and verapamil showed a slight preventive effect on the cholesterol accumulation and on the reduction of elastin content in the aorta without a cholesterol lowering effect in the serum. MgCl2 was more effective than other calcium antagonists and even had a hypocholesterolemic effect. The results indicate that this mouse atherosclerosis model may be usable for primary drug evaluation.

Effects of MK-733 (simvastatin), an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, on intestinal acylcoenzyme A:cholesterol acyltransferase activity in rabbits

MK-733 (simvastatin), a potent 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, was found to inhibit the absorption of cholesterol from the gastrointestinal tract in cholesterol-fed rabbits (Ishida et al. (1988) Biochim. Biophys. Acta 963, 35-41). To clarify the mechanism of action, the effects of MK-733 on acyl coenzyme A:cholesterol acyltransferase (ACAT) and cholesterol esterase activities, which are thought to participate in the absorption of cholesterol, were examined. Dietary administration (0.03% in a 1% cholesterol diet for 7 days, approx. 10 mg/kg) of MK-733 to cholesterol-fed rabbits was found to inhibit the increase in serum total cholesterol levels, and caused a 70% reduction in ACAT activity in microsomes of intestinal mucosa relative to those observed in concurrent control rabbits. MK-733 did not affect cholesterol esterase activity in the cytosol of the intestinal mucosa. The inhibitory effect of MK-733 on cholesterol absorption in cholesterol-fed rabbits is though to be related to a reduction in microsomal ACAT activity in the intestinal mucosa.

Micellar solubilization of cetaben sodium in surfactant and lipid solutions

Cetaben sodium solubilities were evaluated by micellar solubilization in various surfactants and lipid solvents. At pH 8, the relationship between cetaben sodium solubility and surfactant concentration delineated apparent saturable kinetics; at pH 4.9, the relationship between the two parameters was linear. In the presence of 0.5% sodium taurocholate and polysorbate 80, cetaben sodium solubility increased as the medium pH was increased; however, in the presence of 0.5% poloxamer 188, cetaben sodium solubility revealed a hyperbola when the pH was changed from 4.9 to 8.0. Cetaben sodium solubility was enhanced greatly by mixed physiological surfactants, full-strength caprylic-capric monodiglycerides or monodiglycerides, when compared to a single surfactant system. Cetaben sodium solubility is influenced by pH, surfactant type, surfactant concentration, lipid solvent type, and the simultaneous presence of surfactants or phospholipids.