ABSTRACT
The lipophilic 1-substituent in a series of 1-((amidolinked)-alkyl)-pyrimidones, inhibitors of recombinant lipoprotein-associated phospholipase A(2), has been modified to give inhibitors of high potency in human plasma and enhanced physicochemical properties. Phenylpiperazineacetamide derivative 23 shows very promising oral activity.
Subject(s)
Enzyme Inhibitors/pharmacology , Phospholipases A/antagonists & inhibitors , Phospholipases A/blood , 1-Alkyl-2-acetylglycerophosphocholine Esterase , Administration, Oral , Animals , Enzyme Inhibitors/chemical synthesis , Humans , Inhibitory Concentration 50 , Metabolic Clearance Rate/physiology , Microsomes, Liver/metabolism , Piperazines/chemical synthesis , Piperazines/pharmacology , Pyrimidinones/chemical synthesis , Pyrimidinones/pharmacology , Rabbits , RatsABSTRACT
Modification of the pyrimidone 5-substituent in a series of 1-((amidolinked)-alkyl)-pyrimidones, lipophilic inhibitors of lipoprotein-associated phospholipase A2, has given inhibitors of nanomolar potency and improved physicochemical properties. Compound 23 was identified as a potent, highly water soluble. CNS penetrant inhibitor suitable for intravenous administration.
Subject(s)
Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Phospholipases A/antagonists & inhibitors , Pyrimidinones/chemistry , Pyrimidinones/pharmacology , Animals , Arteriosclerosis/drug therapy , Drug Administration Routes , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , Humans , Male , Molecular Structure , Phospholipases A/metabolism , Phospholipases A2 , Pyrimidinones/chemical synthesis , Rabbits , Rats , Solubility , Water/chemistryABSTRACT
From two related series of 2-(alkylthio)-pyrimidones, a novel series of 1-((amidolinked)-alkyl)-pyrimidones has been designed as nanomolar inhibitors of human lipoprotein-associated phospholipase A2. These compounds show greatly enhanced activity in isolated plasma. Selected derivatives such as compounds 51 and 52 are orally active with a good duration of action.
Subject(s)
Enzyme Inhibitors/pharmacology , Lipoproteins/metabolism , Phospholipases A/antagonists & inhibitors , Pyrimidinones/pharmacology , Administration, Oral , Animals , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/chemistry , Molecular Structure , Phospholipases A/metabolism , Phospholipases A2 , Pyrimidinones/administration & dosage , Pyrimidinones/chemistry , RabbitsABSTRACT
SK&F 97426-A is a novel bile acid sequestrant that is threefold more potent than cholestyramine at increasing bile acid excretion in the hamster. SK&F 97426-A is a quaternary alkylammonium polymethacrylate that was selected for comparison with cholestyramine in vivo because of its superior in vitro bile acid binding properties. Association, dissociation, affinity, and capacity experiments were performed under physiologically relevant conditions with the most abundant bile acids found in human bile. The bile acids came to equilibrium with SK&F 97426-A and cholestyramine within approximately 30 min and 6 min, respectively. SK&F 97426-A and cholestyramine had similar capacities for all the bile acids (between 2.5 and 4 mmol/g) and both had similar, very high affinities and slow dissociation rates for the dihydroxy bile acids. However, SK&F 97426-A had much higher affinities for the trihydroxy bile acids glycocholic acid and taurocholic acid than did cholestyramine. Dissociation of glycocholic acid and taurocholic acid from SK&F 97426-A was also much slower (27 and 25%, respectively, dissociated after 60 min) than from cholestyramine (89 and 84%, respectively, dissociated after 60 min). The higher affinities and slower dissociation rates of the trihydroxy bile acids for and from SK&F 97426-A probably account for the increased potency of SK&F 97426-A over cholestyramine in vivo.
Subject(s)
Anticholesteremic Agents/metabolism , Bile Acids and Salts/metabolism , Cholestyramine Resin/metabolism , Polymethacrylic Acids/metabolism , Animals , Anticholesteremic Agents/pharmacokinetics , Cholestyramine Resin/pharmacokinetics , Cricetinae , Humans , Polymethacrylic Acids/pharmacokineticsABSTRACT
In an investigation of novel potential bile acid sequestrants, the affinities of the sodium salts of the glycine and taurine conjugates of naturally occurring bile acids (cholate, deoxycholate, chenodeoxycholate and lithocholate) for several cationic ammonium bile acid derivatives have been investigated by measurements of the extent to which the derivatives are able to precipitate the bile acids. This is roughly proportional to the lipophilicity of the interacting species. Thus, amino and ammonium derivatives of cholic acid do not precipitate taurocholate or glycocholate to any great extent, whereas ammonium derivatives of deoxycholate and lithocholate are much more effective. To complement the precipitation measurements, high resolution 13C-NMR has been applied to investigate the weaker interactions between the ammonium cholate derivative and glycocholate, glycodeoxycholate and glycochenodeoxycholate. Addition of either of the latter two bile acids to the cationic ammonium compound results in considerable broadening of the 13C resonances of both species, indicating the formation of relatively rigid structures. In addition, we have used T2 relaxation enhancement induced by spin-labelled fatty acids to examine the mechanism of interaction with bile acids of amphiphilic anions, which might compete with bile acids for sites on bile acid sequestrants. Low concentrations of 16-DOXY L-Stearate dramatically broaden the 13C-NMR resonances of deoxycholate carbons 19, 18 and 7 in particular, while 5-DOXY L-Stearate exerts much less specific effects. These results have been incorporated into a snapshot model of bile acid-fatty acid interactions.
