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Three water-soluble fibrates (fenofibrate, bezafibrate and chlofibrate) conjugated with a symmetrically branched glyceryl trimer (BGL003) were synthesized, and an evaluation of the fenofibrate-BGL003 conjugate as a candidate for anti-hyperlipemia drug was carried out using rats. The water-solubility of the fenofibrate-BGL003 conjugate was several thousand times greater than that of the original fenofibrate. The lipid-lowering effects of the fenofibrate-BGL003 conjugate were as strong as those of the same grams of fenofibrate. The actual active species of fenofibrate, fenofibric acid, was detected in rats' blood, but neither the fenofibrate-BGL003 conjugate nor fenofibrate was detected, probably due to enzymatic hydrolysis of the ester bond. The plasma concentration of fenofibric acid derived from the fenofibrate-BGL003 conjugate was five times higher than that derived from fenofibrate 4h after administration., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Clofibrate is a lipid-profile modifying agent belonging to the fibrate class of drugs. Fibrates are known to exhibit their beneficial effects by activating peroxisome proliferator-activated receptor-alpha (PPARalpha) and used in the treatment of dyslipidemia and atherosclerosis and for the prevention of heart failure. Hereby, the preparation of two new sets of clofibrate analogues, ethyl 2-(4-chlorophenoxy)-3-oxoalkanoates and ethyl 2-(4-chlorophenoxy)-3-hydroxyalkanoates is described starting from commercially available 3-oxoalkanoates in fair to good yields. Treatment of 3-oxoalkanoates with SO2Cl2 yielded the corresponding 2-chloro-3-oxoalkanoates, that were then converted into 2-(4-chlorophenoxy)-3-oxoalkanoates by reacting with sodium or caesium 4-chlorophenate. Reduction of the keto group with NaBH4 afforded the corresponding 2-(4-chlorophenoxy)-3-hydroxyalkanoates in very high yields and with variable diastereoselectivity. Biological evaluation of the compounds was performed by a transactivation assay in a transiently transfected monkey kidney fibroblast cell line. The newly synthesised clofibrate analogues failed to show noticeable levels of PPAR activation at concentrations where clofibrate showed an evident activity, suggesting that the structural modifications caused the loss of PPAR activity.

The chemistry and pharmacology of the title compound, spirolactone 4, are reported. The synthesis represents a new approach to the preparation of spiro compounds. The pharmacological profiles of 4 are compared to that of clofibrate in Triton-induced hyperlipidemic, sucrose-fed, and normal Sprague-Dawley rat models. Clofibrate was effective in all animal models, but the spirolactone 4 exhibited antitriglyceridemic activity only in the Triton model. The inactivity of 4 in sucrose- and chow-fed rats could not be attributed to a resistance to hydrolysis by serum esterases. Comparative studies revealed that inhibition of hepatic HMG-CoA reductase activity may not be an index of hypocholesterolemic action in sucrose-fed rats. Additionally, only clofibrate exhibited significant changes in components of the hepatic microsomal monooxygenase system.

The synthesis for the title lactone 2, designed to be an antagonist of the enzyme HMG-CoA reductase (E.C.1.1.1.34), is described. Lactone 2, its synthetic tricyclic hemiacetal precursor 4, and clofibrate were investigated for their antilipidemic activity in 7-day treated normal and in Triton WR-1339 induced hyperlipidemic male Sprague-Dawley rats. After 7-day drug administration to normal rats, lactone 2 was less effective than clofibrate in lowering HMG-CoA reductase activity and serum cholesterol; however, unlike clofibrate, lactone 2 did not increase liver weight or liver-body weight ratio or lower serum triglycerides. Since hemiacetal 4 selectively influenced triglycerides in normal animals, lactone 2 and hemiacetal 4 appear to have differential hypolipidemic effects. In the Triton hyperlipidemic model 2 and 4 lowered elevated triglycerides; only 4 significantly reduced elevated cholesterol levels; but neither 2 nor 4 was as effective as clofibrate. Differences in the observed antilipidemic properties for clofibrate, 2, and 4 in the two animal models are discussed. On the basis of preliminary biological data described in this article it is concluded that tricyclic analogues 2 and 4 represent reasonable leads for the development of new antilipidemic agents.

Esters of phenoxyacetic acids and oxyalkyltheophyllines were prepared as potential antihyperlipaemics. The basic idea was to ameliorate the known antilipaemic potency of phenoxyacetic acids and that of clofibric acid as the best known representative, respectively, by using alcoholic ester components with therapeutical efficacy of their own and to expand their therapeutical spectrum. Syntheses and preparative routes of these esters are presented. 1-(Theophyllin-7-yl)-ethyl-2-[2-(p-chlorophenoxy)-2-methyl-propionate] (ML 1024; etofylline clofibrate; Duolip) was selected for further investigations. Characteristics and spectroscopic data of ML 1024 are described.

Ethyl-2(p-chlorophenoxy)-2-methylpropionate (clofibrate) related compounds were synthesized from substituted aryloxy acetic acids (III) either by esterification with selected alcohols (3,3,5-trimethylcyclohexanol and oxyalkyltheophyllines), by introduction into heterocyclic ring system (triazine type) or by amidation (aminotriazines and p-aminobenzoates). Lipid lowering effect was tested in normolipemic and hyperlipemic rats against clofibrate as reference. Some of these derivatives show high activity at low dosage, even under hyperlipemic conditions, whereas clofibrate is only slightly effective. From pharmacological results it can be suggested that the nature of acid group substituent is the main factor for efficacy, while the role of alpha-substituent is important for differentiation of activity against cholesterol and/or triglyceride.

The synthesis of isonicotinic, nicotinic and clofibric esters (III a, b, c) and (IV a, b, c) starting from N-methyl-N-(2-hydroxyethyl or 3-hydroxypropyl)-1,3,3-trimethylbicyclo [2.2.1] heptan-2-endo-amine is described. In general these esters showed a normolipemic activity in rats; in particular, the isonicotinic ester (IV a) showed a hypocholesterolemic activity higher than that of clofibric acid.