ABSTRACT
The discovery of 1-({6-[(2-methoxy-4-propylbenzyl)oxy]-1-methyl-3,4-dihydronaphthalen-2-yl}methyl)azetidine-3-carboxylic acid 13n (ceralifimod, ONO-4641), a sphingosine-1-phosphate (S1P) receptor agonist selective for S1P1 and S1P5, is described. While it has been revealed that the modulation of the S1P1 receptor is an effective way to treat autoimmune diseases such as relapsing-remitting multiple sclerosis (RRMS), it was also reported that activation of the S1P3 receptor is implicated in some undesirable effects. We carried out a structure-activity relationship (SAR) study of hit compound 6 with an amino acid moiety in the hydrophilic head region. Following identification of a lead compound with a dihydronaphthalene central core by inducing conformational constraint, optimization of the lipophilic tail region led to the discovery of 13n as a clinical candidate that exhibited >30â¯000-fold selectivity for S1P1 over S1P3 and was potent in a peripheral lymphocyte lowering (PLL) test in mice (ED50 = 0.029 mg/kg, 24 h after oral dosing).
Subject(s)
Azetidines/pharmacology , Lymphocytes/drug effects , Naphthalenes/pharmacology , Receptors, Lysosphingolipid/agonists , Administration, Oral , Animals , Autoimmune Diseases/drug therapy , Azetidines/administration & dosage , Azetidines/chemistry , Azetidines/pharmacokinetics , CHO Cells , Cricetulus , Female , Humans , Macaca fascicularis , Male , Mice , Mice, Inbred BALB C , Naphthalenes/administration & dosage , Naphthalenes/chemistry , Naphthalenes/pharmacokinetics , Rats, Inbred Lew , Rats, Sprague-DawleyABSTRACT
To construct a non-clinical database for drug-induced QT interval prolongation, the electrophysiological effects of 11 positive and 10 negative compounds on action potentials (AP) in guinea-pig papillary muscles were investigated in a multi-site study according to a standard protocol. Compounds with a selective inhibitory effect on the rapidly activated delayed rectifier potassium current (IKr) prolonged action potential duration at 90% repolarization (APD90) in a concentration-dependent manner, those showing Ca2+ current (ICa) inhibition shortened APD30, and those showing Na+ current (INa) inhibition decreased action potential amplitude (APA) and Vmax. Some of the mixed ion-channel blockers showed a bell-shaped concentration-response curve for APD90, probably due to their blockade of INa and/or ICa, sometimes leading to a false-negative result in the assay. In contrast, all positive compounds except for terfenadine and all negative compounds with IKr-blocking activity prolonged APD30-90 regardless of their INa- and/or ICa-blocking activities, suggesting that APD30-90 is a useful parameter for evaluating the IKr-blocking activity of test compounds. Furthermore, the assay is highly informative regarding the modulation of cardiac ion channels by test compounds. Therefore, when APD90 and APD30-90 are both measured, the action potential assay can be considered a useful method for assessing the risk of QT interval prolongation in humans in non-clinical safety pharmacology studies.
Subject(s)
Action Potentials/drug effects , Biological Assay , Long QT Syndrome/chemically induced , Papillary Muscles/drug effects , Animals , Databases, Factual , Guinea Pigs , In Vitro Techniques , Male , Papillary Muscles/physiology , Pharmaceutical PreparationsABSTRACT
Certain compounds that prolong QT interval in humans have little or no effect on action-potential (AP) duration used traditionally, but they inhibit rapidly-activated-delayed-rectifier potassium currents (IKr) and/or human ether-a-go-go-related gene (hERG) currents. In this study using isolated guinea-pig papillary muscles, we investigated whether new parameters in AP assays can detect the inhibitory effects of various compounds on IKr and/or hERG currents with high sensitivity. The difference in AP duration between 60% and 30% repolarization, 90% and 60% repolarization, and 90% and 30% repolarization (APD30-60, APD60-90, and APD30-90, respectively) were calculated as the new parameters. All the 15 IKr and/or hERG current inhibitors that have been reported (9 compounds) or not reported (6 compounds) to inhibit calcium currents prolonged APD30-60, APD60-90, and/or APD30-90; and 8 of the 15 inhibitors prolonged APD30-60, APD60-90, and/or APD30-90 more potently than APD90. The APD30-60, APD60-90, and APD30-90 measurements revealed no difference in sensitivity when evaluating the effects of the IKr and/or hERG current inhibitors on the three parameters. On the other hand, compounds with little or no effect on hERG currents had no effect on APD30-60, APD60-90, or APD30-90. Therefore, it is concluded that in AP assays using isolated guinea-pig papillary muscles, APD30-60, APD60-90, and APD30-90 are useful indexes for evaluating the inhibitory effects of compounds including mixed ion-channel blockers on IKr and/or hERG currents.
Subject(s)
Action Potentials/drug effects , Calcium Channel Blockers/pharmacology , Long QT Syndrome/chemically induced , Papillary Muscles/drug effects , Potassium Channel Blockers/pharmacology , Animals , Databases, Factual , Delayed Rectifier Potassium Channels/antagonists & inhibitors , Delayed Rectifier Potassium Channels/physiology , Ether-A-Go-Go Potassium Channels/antagonists & inhibitors , Ether-A-Go-Go Potassium Channels/physiology , Guinea Pigs , In Vitro Techniques , Male , Papillary Muscles/physiologyABSTRACT
The effect of a selective inducible nitric oxide synthase inhibitor, ONO-1714 ((1S,5S,6R,7R)-7-chloro-3-imino-5-methyl-2-azabicyclo[4.1.0]heptane hydrochloride), on hemodialysis-related hypotension was investigated using a canine model of renal dysfunction. Renal dysfunction was induced in dogs by complete bilateral ligation of renal arteries. On performing hemodialysis with ultrafiltration, the blood pressure of the renal dysfunction dogs gradually decreased and persisted at reduced levels until completion. ONO-1714 ameliorated the hemodialysis-induced hypotension in the renal dysfunction dogs at a dose that did not influence blood pressure in non-hemodialysis dogs with normal renal function. The above findings indicated that ONO-1714 may elicit beneficial effects on hemodialysis-related hypotension.
Subject(s)
Amidines/therapeutic use , Heterocyclic Compounds, 2-Ring/therapeutic use , Hypotension/drug therapy , Kidney Diseases/drug therapy , Kidney Diseases/physiopathology , Nitric Oxide Synthase/antagonists & inhibitors , Renal Dialysis/methods , Amidines/pharmacology , Animals , Dogs , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Heterocyclic Compounds, 2-Ring/pharmacology , Hypotension/enzymology , Kidney Diseases/enzymology , Kidney Function Tests , Male , Nitric Oxide Synthase/metabolism , Nitric Oxide Synthase Type IIABSTRACT
To clarify the role of nitric oxide (NO) in hemodialysis (HD)-related hypotension, the relationship between plasma NO metabolites (NOx) and blood pressure changes, and the effect of N(G)-monomethyl-L-arginine (L-NMMA), a NO synthase inhibitor, on changes in blood pressure were evaluated in an experimental renal dysfunctional dog model. In order to create a renal dysfunction model, gentamicin was administered to male beagles in which 7 of 8 renal artery branches had been ligated. Normal renal functional and dysfunctional dogs underwent 3 hr of HD per day for 3 days. HD induced a transient decrease in mean blood pressure in the normal renal functional dogs. In renal dysfunctional dogs, a continuous hypotension occurred with a gradual increase in the plasma NOx concentration during HD. Although L-NMMA prevented the fall in blood pressure, it did not significantly change the plasma NOx concentration during HD. These results suggest that NO contributes to HD-related hypotension in renal dysfunctional dogs but the plasma NOx concentration does not reflect the change in blood pressure.
Subject(s)
Hypotension/etiology , Nitric Oxide/blood , Renal Dialysis/adverse effects , Renal Insufficiency/therapy , Animals , Blood Urea Nitrogen , Creatinine/blood , Disease Models, Animal , Dogs , Heart Rate , Male , Reference ValuesABSTRACT
A series of 2-iminopiperidines fused to small-membered rings (Tables 1 and 2) were synthesised and biologically evaluated using an in vitro human nitric oxide synthase (NOS) inhibition assay. Fused bicyclic compounds 5-9 exhibited nearly the same potency as compound 1 in the hiNOS inhibition assay. Among these, the 1-methyl analogues 8 and 9 showed better isoform selectivity than their corresponding unsubstituted analogues 7 and 6, respectively. Compounds 5 and 6 were also evaluated by an in vivo NO accumulation assay in a mouse model. The discovery process of new chemical leads for an orally bioavailable inhibitor of human inducible NOS (iNOS) is reported. The structure-activity relationship (SAR) study and chemistry of these compounds are also reported.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Nitric Oxide Synthase/antagonists & inhibitors , Piperidines/chemical synthesis , Piperidines/pharmacology , Administration, Oral , Animals , Biological Availability , Drug Design , Enzyme Inhibitors/toxicity , Humans , Indicators and Reagents , Isoenzymes/antagonists & inhibitors , Kinetics , Mice , Mice, Inbred BALB C , Nitric Oxide Synthase Type II , Recombinant Proteins/drug effects , Structure-Activity Relationship , Substrate Specificity , omega-N-Methylarginine/pharmacologyABSTRACT
Further chemical modification of 2-iminopiperidines fused to cyclopropane rings was performed. Optically active isomers 2 and 13 were synthesized and their biological activity was evaluated. Compound 2 exhibited greater potency and more isoform selectivity than enantiomer 13 in the iNOS inhibition assay. One of the gem-chlorines on the fused cyclopropane moiety of 2 was eliminated to produce 3, which showed reduced potency for iNOS inhibition, as well as 4 with an increased potency. The isoform selectivity of 4 was also much higher than that of 3. This was also true for the corresponding methyl derivatives 6-9. The structure-activity relationship (SAR) study and computer aided docking study of the most optimized structure 4 with human iNOS will also be reported.
Subject(s)
Bridged Bicyclo Compounds/chemical synthesis , Bridged Bicyclo Compounds/pharmacology , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Imines/chemical synthesis , Imines/pharmacology , Nitric Oxide Synthase/antagonists & inhibitors , Animals , Biological Availability , Bridged Bicyclo Compounds/chemistry , Bridged Bicyclo Compounds/toxicity , Crystallography, X-Ray , Cyclopropanes/chemical synthesis , Cyclopropanes/chemistry , Cyclopropanes/pharmacology , Drug Design , Enzyme Inhibitors/toxicity , Humans , Imines/chemistry , Imines/toxicity , Inhibitory Concentration 50 , Magnetic Resonance Spectroscopy , Mice , Mice, Inbred BALB C , Nitric Oxide Synthase/genetics , Nitric Oxide Synthase Type II , Piperidines/chemical synthesis , Piperidines/chemistry , Piperidines/pharmacology , Recombinant Proteins/antagonists & inhibitors , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Structure-Activity Relationship , omega-N-Methylarginine/pharmacologyABSTRACT
The process of discovery and biological evaluation of alpha,beta-unsaturated cyclic amidines, as selective inhibitors of inducible nitric oxide synthase (iNOS), is reported. Dihydropyridin-2(1H)-imines and 1,5,6,7-tetrahydro-2H-azepin-2-imines were synthesized and biologically evaluated both in vitro and in vivo using a nitric oxide synthase inhibition assay. Compounds 1, 5, 6, 8-12 and 16 exhibited potent inhibition of iNOS. Among these, compounds 6, 7, 10, 11 and 16 showed 5- to 19-fold isoform selectivity. Compounds 1, 6, 10, 11 and 16 also showed potent inhibitory activity in the NOx accumulation assay in mice. Compounds 1 and 6 showed excellent bioavailability (BA) in rats when administered orally. Full details are presented here, including the structure-activity relationship (SAR) studies, the chemistry of these compounds, and the pharmacokinetic data and the computer-aided docking study of 10 with hiNOS.
Subject(s)
Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Imines/chemical synthesis , Imines/pharmacology , Nitric Oxide Synthase/antagonists & inhibitors , Pyridines/chemical synthesis , Pyridines/pharmacology , Animals , Biological Availability , Computer Simulation , Drug Design , Enzyme Inhibitors/pharmacokinetics , Indicators and Reagents , Injections, Intravenous , Isoenzymes/antagonists & inhibitors , Kinetics , Mass Spectrometry , Mice , Models, Molecular , Molecular Conformation , Nitrates/metabolism , Nitric Oxide Synthase Type II , Rats , Recombinant Proteins/chemistry , Structure-Activity RelationshipABSTRACT
Dihydropyridin-2-imines were synthesized and biologically evaluated both in vitro and in vivo using a nitric oxide inhibition assay. Compounds 1, 4, 5 and 7-11 exhibited potent activity in the inducible nitric oxide (iNOS) inhibition assay. Of these 5, 6, 9 and 10 showed 5- to 11-fold increases in isoform selectivity. Compounds 1, 5, 9 and 10 showed potent inhibitory activity in the NOx accumulation assay in mice. Compounds 1 and 5 also showed good bioavailability (BA) when given orally.
