John R. Regan

RG 12561 (dalvastatin): a novel synthetic inhibitor of HMG-CoA reductase and cholesterol-lowering agent.

RG 12561 (dalvastatin) is a prodrug which converts to its open hydroxyacid form in the body. The Na salt of RG 12561 (RG 12561-Na) is a potent inhibitor of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme in the cholesterol biosynthetic pathway. It competitively inhibits rat liver HMG-CoA reductase with an IC50 value of 3.4 nmol/l. In the same assay, the IC50 values for other potent HMG-CoA reductase inhibitors, lovastatin-Na and pravastatin, were 2.3 and 8.9 nmol/l, respectively. In Hep G2 liver cells, RG 12561-Na, lovastatin-Na and pravastatin inhibited cholesterol biosynthesis from radiolabeled octanoate with IC50 values of 4 and 5 nmol/l and 1.1 mumol/l, respectively. In a rat ex vivo assay, orally administered RG 12561, lovastatin and pravastatin inhibited cholesterol biosynthesis in liver slices with ED50 values of 0.9, 0.5 and 12 mg/kg, respectively. In cholestyramine-fed hamsters, RG 12561 (0.1% in food for 18 days) reduced LDL cholesterol, whereas HDL was slightly increased. The reductions in the LDL/HDL ratio for RG 12561, RG 12561-Na, lovastatin and lovastatin-Na were 35, 76, 88 and 88%, respectively. At a higher dose, RG 12561 (0.4% in food) reduced serum cholesterol, LDL and LDL/HDL by 84, 97 and 91%, respectively. In WHHL rabbits, RG 12561 and lovastatin (5 mg/kg, b.i.d., 12 days) reduced serum cholesterol by 17 and 16%, respectively. These results demonstrate that RG 12561 is a potent cholesterol-lowering agent.

Benzofuran based PDE4 inhibitors

Replacement of the 3,4-dialkoxyphenyl substructure common to a number of PDE4 inhibitors with a 2-alkyl-7-methoxybenzofuran unit is described. This substitution can result in either enhancement or substantial reductions in PDE4 inhibitory activity depending on the system to which it is applied. An in vitro SAR study of a potent series of 4-(2-heteroaryl-ethyl)-benzoiurans 26 is also presented.

Mimicry of Biological Macromolecules by Polyaromatic Anionic Compounds

The preparation, characterization and biological properties of some polyanionic polymers are reported. These polymers are constructed with repeating phenol-based monomers. The anionic groups attached to the aro matic nucleus provide the basis for binding to basic domains of proteins. Scaf fold flexibility permits the polyanionic polymers to adopt low energy conforma tions suitable for interacting with coagulation proteins and an anti-DNA monoclonal antibody. Structure activity relationships (SAR) and comparisons with aurintricarboxylic acid are described. The polymers doubled the clotting time in the APTT assay with value ranging from 10-1000 μg/mL. Binding to an anti-DNA monoclonal antibody occurred with ICso values of 0.3-5.0 μg/mL.

2-Substituted-4-methoxybenzimidazole-based PDE4 inhibitors

A new family of PDE4 inhibitors based on a benzimidazole framework is described. Several of these compounds are orally bioavailable and show efficacy in in vivo models of inflammatory disease.

Novel cytokine release inhibitors. Part IV: Analogs of podocarpic acid

Podocarpic acid derivatives as cytokine (IL-1beta) release inhibitors are discussed.

Inhibitors of HMG-CoA reductase. Biological effects of A 6-[2-[2-(4-fluoro-3-methylphenyl)-4-substituted cyclohexe-1-en-1-yl]ethenyl]-4-hydroxy-3,4,5,6-tetrahydro-2h-pyran-2-one

Abstract We report on a series of potent inhibitors of HMG-CoA reductase (HMGR) that were designed to examine the biological consequences that result from molecular changes in RG 12561. The introduction of functional groups on the cyclohexene nucleus of RG 12561 and the resulting inhibitor-enzyme interactions at remote binding sites of HMGR are discussed. Cellular membrane permeability may also contribute to potency. The HMGR inhibitory activity was measured utilizing solubilized enzyme. The compounds were evaluated as inhibitors of sterol biosynthesis in vitro using liver slices and in vivo after oral administration to the rat.