ABSTRACT
Glyphosate-based herbicide (GBH) applications were reported to induce physiological damages to glyphosate-resistant (GR) soybean, which were mainly attributed to aminomethylphosphonic acid (AMPA). In order to study glyphosate and AMPA dynamics in plants and associated phytotoxic effects, a greenhouse experiment was set where GR soybeans were exposed to GBH (0.7 to 4.5 kg glyphosate ha-1) and sampled over time (2, 7, 14, and 28 days after treatment (DAT)). Hydrogen peroxide content increased 2 DAT, while a decrease was observed for the effective quantum yield (2, 7, 14 DAT), stomatal conductance (2 DAT), and biomass (14 DAT). Glyphosate content was higher in leaves, followed by stems, and then roots. AMPA content tended to increase with time, especially in roots, and the amount of AMPA in roots was negatively correlated to mostly all phytotoxicity indicators. This finding is important since AMPA residues are measured in agricultural soils several months after GBH applications, which could impact productivity in GR crops.
Subject(s)
Glycine max/chemistry , Glycine/analogs & derivatives , Herbicide Resistance , Herbicides/analysis , Organophosphorus Compounds/analysis , Glycine/analysis , Glycine/metabolism , Glycine/pharmacology , Herbicides/metabolism , Herbicides/pharmacology , Organophosphorus Compounds/metabolism , Plant Leaves/chemistry , Plant Leaves/drug effects , Plant Leaves/metabolism , Plant Roots/chemistry , Plant Roots/drug effects , Plant Roots/metabolism , Plant Stems/chemistry , Plant Stems/drug effects , Plant Stems/metabolism , Glycine max/drug effects , Glycine max/metabolism , GlyphosateABSTRACT
The optimization of a novel series of non-nucleoside reverse transcriptase inhibitors (NNRTI) led to the identification of pyridone 36. In cell cultures, this new NNRTI shows a superior potency profile against a range of wild type and clinically relevant, resistant mutant HIV viruses. The overall favorable preclinical pharmacokinetic profile of 36 led to the prediction of a once daily low dose regimen in human. NNRTI 36, now known as MK-1439, is currently in clinical development for the treatment of HIV infection.
Subject(s)
Anti-HIV Agents/pharmacology , Drug Discovery , Drug Resistance, Viral/drug effects , HIV-1/drug effects , Pyridones/chemistry , Pyridones/pharmacology , Reverse Transcriptase Inhibitors/chemical synthesis , Reverse Transcriptase Inhibitors/pharmacology , Triazoles/chemistry , Triazoles/pharmacology , Animals , Anti-HIV Agents/chemical synthesis , Anti-HIV Agents/chemistry , Cells, Cultured , Crystallography, X-Ray , Dogs , HIV-1/genetics , Humans , Inhibitory Concentration 50 , Molecular Structure , Mutation , Rats , Rats, Sprague-Dawley , Reverse Transcriptase Inhibitors/chemistryABSTRACT
The discovery of highly potent and selective second generation EP(4) antagonist MK-2894 (34d) is discussed. This compound exhibits favorable pharmacokinetic profile in a number of preclinical species and potent anti-inflammatory activity in several animal models of pain/inflammation. It also shows favorable GI tolerability profile in rats when compared to traditional NSAID indomethacin.
Subject(s)
Analgesics/chemical synthesis , Benzoates/chemical synthesis , Cyclopropanes/chemical synthesis , Prostaglandin Antagonists/chemical synthesis , Receptors, Prostaglandin E/metabolism , Thiophenes/chemical synthesis , Analgesics/chemistry , Analgesics/pharmacokinetics , Animals , Benzoates/chemistry , Benzoates/pharmacokinetics , Cyclopropanes/chemistry , Cyclopropanes/pharmacokinetics , Half-Life , Humans , Magnetic Resonance Spectroscopy , Male , Pain/drug therapy , Prostaglandin Antagonists/chemistry , Prostaglandin Antagonists/pharmacokinetics , Rats , Rats, Sprague-Dawley , Receptors, Prostaglandin E/antagonists & inhibitors , Structure-Activity Relationship , Thiophenes/chemistry , Thiophenes/pharmacokineticsABSTRACT
The discovery of novel and selective inhibitors of human 5-lipoxygenase (5-LO) is described. These compounds are potent, orally bioavailable, and active at inhibiting leukotriene biosynthesis in vivo in a dog PK/PD model. A major focus of the optimization process was to reduce affinity for the human ether-a-go-go gene potassium channel while preserving inhibitory potency on 5-LO. These efforts led to the identification of inhibitor (S)-16 (MK-0633, setileuton), a compound selected for clinical development for the treatment of respiratory diseases.
ABSTRACT
Phosphodiesterase-4 (PDE 4) enzyme inhibitors have been shown to have anti-inflammatory properties in various animal disease processes and therefore could be effective drugs for the treatment of equine airway diseases. The purpose of this study was to evaluate the efficacy and adverse effects of the PDE 4 inhibitor L-826,141 in horses with heaves. In a blinded parallel design, horses with heaves exposed daily to moldy hay were given a placebo for 14 days and then administered either L-826,141 (n = 6; loading dose of 1 mg/kg IV followed by 0.5 mg/kg IV q48h) or dexamethasone (n = 6; 0.04 mg/kg IV q24h) from days 15 to 29 (study 1). Pulmonary function and bronchoalveolar (BAL) cytology were evaluated weekly from baseline (day 0) to 29 days. In study 2, horses were treated with L-826,141 (1.0 mg/kg IV q24h) for 8 days. Although ex vivo lipopolysaccharide-induced tumor necrosis factor (TNF)-alpha and LTB4 production by fresh blood were inhibited up to 90% after repeated administrations of L-826,141, this treatment failed to improve lung function. In contrast, dexamethasone (positive control) treatment resulted in significant improvement in lung mechanics and airway function in all horses. Neither drug had a significant effect on BAL total cell counts and differential cytology. Administration of the PDE 4 inhibitor L-826,141 for up to 14 days to horses with heaves was not associated with an improvement in airway function or inflammation. These findings suggest that the PDE 4 enzyme is not a key mediator of lung inflammation in heaves.
Subject(s)
3',5'-Cyclic-AMP Phosphodiesterases/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Horse Diseases/drug therapy , Lung Diseases, Obstructive/veterinary , Pyridines/pharmacology , Animals , Cyclic Nucleotide Phosphodiesterases, Type 4 , Dose-Response Relationship, Drug , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/therapeutic use , Horses , Leukotriene B4/metabolism , Lung Diseases, Obstructive/drug therapy , Lung Diseases, Obstructive/metabolism , Pyridines/administration & dosage , Pyridines/therapeutic use , Treatment Outcome , Tumor Necrosis Factor-alpha/metabolismABSTRACT
The synthesis and the EP(1) receptor binding affinity of 2,3-diarylthiophene derivatives are described. The evaluation of the structure-activity relationship (SAR) in this series led to the identification of compounds 4, 7, and 12a, which exhibit high affinity for the human EP(1) receptor and a selectivity greater than 100-fold against the EP(2), EP(3), EP(4), DP, FP, and IP receptors and greater than 25-fold versus the TP receptor. These three antagonists present good pharmacokinetics in rats and significant differences in the way they are distributed in the brain.
Subject(s)
Receptors, Prostaglandin E/antagonists & inhibitors , Thiophenes/chemical synthesis , Thiophenes/pharmacokinetics , Animals , Brain/metabolism , Cell Line , Half-Life , Humans , Pharmacokinetics , Rats , Receptors, Prostaglandin E, EP1 Subtype , Structure-Activity Relationship , Thiophenes/pharmacology , Tissue DistributionABSTRACT
A SAR study on the tertiary alcohol series of phosphodiesterase-4 (PDE4) inhibitors related to 1 is described. In addition to inhibitory potency against PDE4 and the lipopolysaccharide-induced production of TNFalpha in human whole blood, the binding affinity of these compounds for the human ether-a-go-go related gene (hERG) potassium channel (an in vitro measure for the potential to cause QTc prolongation) was assessed. Four key structural moieties in the molecule were studied, and the impact of the resulting modifications in modulating these activities was evaluated. From these studies, (+)-3d (L-869,298) was identified as an optimized structure with respect to PDE4 inhibitory potency, lack of binding affinity to the hERG potassium channel, and pharmacokinetic behavior. (+)-3d exhibited good in vivo efficacy in several models of pulmonary function with a wide therapeutic index with respect to emesis and prolongation of the QTc interval.
Subject(s)
3',5'-Cyclic-AMP Phosphodiesterases/antagonists & inhibitors , Alcohols/chemical synthesis , Cyclic N-Oxides/chemical synthesis , Phosphodiesterase Inhibitors/chemical synthesis , Potassium Channels, Voltage-Gated , Potassium Channels/metabolism , Pyridines/chemical synthesis , Alcohols/pharmacokinetics , Alcohols/pharmacology , Alcohols/toxicity , Animals , Bronchoconstriction/drug effects , Crystallography, X-Ray , Cyclic N-Oxides/pharmacokinetics , Cyclic N-Oxides/pharmacology , Cyclic N-Oxides/toxicity , Cyclic Nucleotide Phosphodiesterases, Type 4 , Dogs , ERG1 Potassium Channel , Electrocardiography , Ether-A-Go-Go Potassium Channels , Guinea Pigs , Humans , In Vitro Techniques , Long QT Syndrome/chemically induced , Phosphodiesterase Inhibitors/pharmacokinetics , Phosphodiesterase Inhibitors/pharmacology , Phosphodiesterase Inhibitors/toxicity , Protein Binding , Pyridines/chemistry , Pyridines/pharmacokinetics , Pyridines/pharmacology , Pyridines/toxicity , Rats , Saimiri , Sheep , Stereoisomerism , Structure-Activity Relationship , Tumor Necrosis Factor-alpha/biosynthesis , Vomiting/chemically inducedABSTRACT
The synthesis and the phosphodiesterase-4 (PDE4) inhibitory activity of 2-pyridinemethanol derivatives is described. The evaluation of the structure-activity relationship (SAR) in this series of novel PDE4 inhibitors led to the identification of compound 9 which exhibits excellent in vitro activity, desirable pharmacokinetic parameters and good efficacy in animal models of bronchoconstriction.
Subject(s)
3',5'-Cyclic-AMP Phosphodiesterases/antagonists & inhibitors , Phosphodiesterase Inhibitors/chemistry , Phosphodiesterase Inhibitors/pharmacology , Picolines/chemistry , Picolines/pharmacology , Administration, Oral , Animals , Biological Availability , Cyclic Nucleotide Phosphodiesterases, Type 4 , Half-Life , Humans , Inhibitory Concentration 50 , Phosphodiesterase Inhibitors/chemical synthesis , Phosphodiesterase Inhibitors/pharmacokinetics , Picolines/chemical synthesis , Picolines/pharmacokinetics , Rats , Saimiri , Stereoisomerism , Structure-Activity Relationship , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Tumor Necrosis Factor-alpha/biosynthesisABSTRACT
The synthesis and the biological evaluation of new potent phosphodiesterase type 4 (PDE4) inhibitors are presented. This new series was elaborated by replacement of the metabolically resistant phenyl hexafluorocarbinol of L-791,943 (1) by a substituted aminopyridine residue. The structure-activity relationship of N-substitution on 3 led to the identification of (-)-3n which exhibited a good PDE4 inhibitor activity (HWB-TNFalpha=0.12 microM) and an improved pharmacokinetic profile over L-791,943 (rat t(1/2)=2 h). (-)-3n was well tolerated in ferret with an emetic threshold of 30 mg/kg (po) and was found to be active in the ovalbumin-induced bronchoconstriction model in guinea pig (54%, 0.1 mg/kg, ip) as well as the ascaris-induced bronchoconstriction model in sheep (64%/97%, early/late, 0.5 mg/kg, iv).
Subject(s)
3',5'-Cyclic-AMP Phosphodiesterases/antagonists & inhibitors , Aminopyridines/chemical synthesis , Aminopyridines/pharmacology , Aminopyridines/pharmacokinetics , Animals , Bronchoconstriction/drug effects , Cyclic Nucleotide Phosphodiesterases, Type 4 , Drug Evaluation, Preclinical , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/pharmacology , Ferrets , Guinea Pigs , Half-Life , Humans , Inhibitory Concentration 50 , Rats , Sheep , Structure-Activity Relationship , Therapeutic Equivalency , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Vomiting/chemically inducedABSTRACT
A detailed SAR study directed toward the optimization of pharmacokinetic parameters for analogues of L-791,943 is reported. The introduction of a soft metabolic site on this structure permitted the identification of L-826,141 as a potent phosphodiesterase type 4 (PDE4) inhibitor that is well absorbed and that presents a shorter half-life than L-791,943 in a variety of animal species. The efficacy of L-826,141 is also demonstrated in different in vivo models.
Subject(s)
3',5'-Cyclic-AMP Phosphodiesterases/antagonists & inhibitors , Phosphodiesterase Inhibitors/chemical synthesis , Phosphodiesterase Inhibitors/pharmacology , Alkylation , Animals , Biological Availability , Cell Line , Cyclic Nucleotide Phosphodiesterases, Type 4 , Half-Life , Humans , Indicators and Reagents , Phosphodiesterase Inhibitors/pharmacokinetics , Pyridines/chemical synthesis , Pyridines/pharmacokinetics , Pyridines/pharmacology , Rats , Structure-Activity Relationship , Tumor Necrosis Factor-alpha/chemical synthesis , Tumor Necrosis Factor-alpha/pharmacologyABSTRACT
A detailed study directed towards metabolic stability optimization of the alkoxy substituents on the catechol moiety of CDP-840 is reported. Replacement of the methoxy and cyclopentyloxy substituents by cyclobutyloxy and/or difluromethoxy groups resulted in the discovery of potent and selective PDE4 inhibitors where the formation of reactive metabolites that could covalently bind to microsomal protein was significantly reduced or eliminated.
Subject(s)
3',5'-Cyclic-AMP Phosphodiesterases/antagonists & inhibitors , Catechols/chemistry , Pyridines/chemistry , Pyridines/pharmacology , Animals , Cyclic Nucleotide Phosphodiesterases, Type 4 , Microsomes, Liver/chemistry , Microsomes, Liver/metabolism , Molecular Structure , Protein Binding , Pyridines/metabolism , Rats , Structure-Activity RelationshipABSTRACT
Structure-activity relationship studies directed toward improving the potency and metabolic stability of CDP-840 (3) resulted in the discovery of L-791,943 (11n) as a potent (HWB TNF-alpha = 0.67 microM) and orally active phosphodiesterase type 4 (PDE4) inhibitor. This compound, which bears a stable bis-difluoromethoxy catechol and a pendant hexafluorocarbinol, exhibited a long half-life in rat and in squirrel monkey. It is well tolerated in ferret with an emetic threshold greater than 30 mg/kg (po) and was found to be active in the ovalbumin-induced bronchoconstriction model in guinea pig and in the ascaris-induced bronchoconstriction models in sheep and squirrel monkey.