Investigation of 3,5-isoxazolidinediones as hypolipidemic agents in rodents.

A series of 2-benzoyl-4,4-dialkyl-3,5-isoxazolidinediones proved to have potent hypolipidemic activity, lowering both serum cholesterol and triglyceride levels at 10 or 20 mg/kg/day, IP and orally in rodents. 2-(3,4,5-Trimethoxybenzoyl)-4,4-diethyl-3,5-isoxazolidinedione+ ++ (4) afforded the best hypolipidemic activity lowering normolipidemic CF1 mouse serum cholesterol levels 49% and serum triglyceride levels 34% at 20 mg/kg/day, IP. Compound 4 was selected as a typical derivative of the chemical class for further detailed studies. Serum cholesterol levels in normolipidemic Sprague Dawley male rats were reduced 45% after 8 weeks at 10 and 20 mg/kg/day of compound, orally. Serum triglyceride levels were reduced 38-49% at 10 and 20 mg/kg/day, orally. In vitro liver enzyme activities studies in normolipidemic CF1 mice showed the compound inhibited mitochondrial citrate exchange, acetyl CoA synthetase, HMG CoA reductase, acyl CoA cholesterol acyl transferase, acetyl CoA carboxylase, sn-glycerol-3-phosphate acyl transferase, phosphatidylate phosphohydrolase and heparin-induced lipoprotein lipase activities with increases in the activities of cholesterol ester hydrolase and ATP-dependent citrate lyase. Similar enzyme activities were inhibited in vivo except HMG CoA reductase activity was not inhibited in rat liver or small intestinal mucosa after 8 weeks drug administration. Cholesterol levels were reduced in tissues after 8 weeks administration of compound 4 in normolipidemic rats. Bile cholesterol and triglyceride levels were elevated after two weeks administration to rats at 20 mg/kg/day. Serum lipoprotein levels in normolipidemic and hyperlipidemic rats showed the cholesterol levels in VLDL and LDL fractions after 4, 6 and 8 weeks at 10 and 20 mg/kg/day were reduced whereas HDL-cholesterol levels were significantly elevated. Studies demonstrated that 3H-cholesterol and 14C-palmitic acid incorporation into lipids of the lipoprotein fraction was reduced by the drug but 32P-incorporation was generally elevated. The agent demonstrated no observable toxicity in rats after 8 weeks administration, orally. The acute toxicity study in normolipidemic mice at 20, 40 and 100 mg/kg/day, IP, demonstrated no observable harmful effects of the drug.

The hypolipidemic effects of 1-acetyl-4-phenyl-1,2,4-triazolidine-3,5-dione in rodents.

1-Acetyl-4-phenyl-1,2,4-triazolidine,5-dione (APTD), a potent hypolipidemic agent, lowered both serum cholesterol and triglyceride levels in normo- and hyperlipidemic rats at 10 or 20 mg/kg/day. The agent effectively lowered VLDL-cholesterol (VLDL-C) and LDL-C content and raised HDL-C content in normal and hyperlipidemic rats treated from 4 to 8 weeks. Similar effects on the incorporation of cholesterol into the lipoprotein fractions were observed after drug treatment. Tissue lipids, e.g. cholesterol, were lowered, whereas fecal cholesterol levels were increased. APTD's primary targets were acyl CoA cholesterol acyl transferase (ACAT) for cholesterol ester synthesis and sn-glycerol-3-phosphate acyl transferase (GPAT) and phosphatidylate phosphohydrolase (PPH) for triglyceride synthesis.

The anti-inflammatory activity of 5H-dibenz[c,e]azepine-5,7(6H)dione, 6,7-dihydro-5H-dibenz[c,e]azepine, N-benzoylbenzamide and 1H-benz[d,e]isoquinoline-1,3(2H)dione derivatives in rodents.

A series of N-substituted 5H-dibenz[c,e]azepin-5,7(6H)dione, 6-substituted 6,7-dihydro-5H-dibenz[c,e]azepine, 1H-benz[d,e]isoquinoline-1,3(2H)dione and N-benzoyl derivatives was shown to have anti-inflammatory and local analgesic activity in rodents. 6-(4-Chlorophenyl)-5H-dibenz[c,e]azepin-5,7(6H)dione demonstrated greater than 50% inhibition of induced edema and the writhing reflex at 25 mg/kg, I.P. in mice. 6-Methyl-6,7-dihydro-5H-dibenz[c,e]azepine and the N-butyl and N-pentyl derivatives of the dibenz-[c,e]azepine and N-benzoylbenzamide series demonstrated potent activity in both screens. The 1H-benz[d,e]isoquinoline-1,3(2H)diones were generally less active than the other three chemical classes of agents tested. However, the 2-(methylthio)ethyl derivative of this series demonstrates good activity in both screens. These agents appeared to be as potent as the standards, indomethacin and phenylbutazone, as anti-inflammatory agents in these animal models. Selected agents, e.g. 6-(4-methylphenyl)-5H-dibenz[c,e]azepin-5,7(6H)dione demonstrated anti-arthritic and anti-gout activities in rodents. The N-methyl and N-butyl derivatives of 6,7-dihydro-5H-dibenz[c,e]azepine afforded good anti-pleurisy activity in rats at 25 mg/kg x 2. The agents which demonstrated potent anti-inflammatory action were found to inhibit acid lysosomal hydrolytic enzyme activities in mouse liver and macrophages at 10(-5) M concentrations. Trypsin, elastase and collagenase activities were also inhibited by the derivatives. Prostaglandin synthetase activity of bovine seminal vesicles and mouse macrophages was inhibited by the compounds at 10(-5) M concentrations.