ABSTRACT
We have systematically studied the effects of varying the central unnatural amino acid moiety on CGRP receptor antagonist potency and CYP inhibition in a series of ureidoamides. In this Letter, we report the discovery of compound 23, a potent CGRP receptor antagonist with only weak CYP3A4 inhibition. Unlike the triptans, compound 23 did not cause active constriction of ex vivo human cerebral arteries. At doses of 0.3-1 mg/kg (s.c.), 23 showed robust inhibition of CGRP-induced increases in marmoset facial blood flow, a validated migraine model. Ureidoamide 23 derives from a novel amino acid, 1H-indazol-5-yl substituted alanine as a tyrosine surrogate.
Subject(s)
Calcitonin Gene-Related Peptide Receptor Antagonists , Animals , Callithrix , Coronary Vessels/drug effects , Cytochrome P-450 CYP3A Inhibitors , Humans , In Vitro Techniques , Molecular Structure , Structure-Activity Relationship , Tyrosine/chemistryABSTRACT
Calcitonin gene-related peptide (CGRP) has been implicated in the pathogenesis of migraine. Early chemistry leads suffered from modest potency, significant CYP3A4 inhibition, and poor aqueous solubility. Herein, we describe the optimization of these leads to give 4 (BMS-694153), a molecule with outstanding potency, a favorable predictive toxicology profile, and remarkable aqueous solubility. Compound 4 has good intranasal bioavailability in rabbits and shows dose-dependent activity in validated in vivo and ex vivo migraine models.
Subject(s)
Calcitonin Gene-Related Peptide Receptor Antagonists , Indazoles/therapeutic use , Migraine Disorders/drug therapy , Quinazolinones/therapeutic use , Administration, Intranasal , Animals , Biological Availability , Calcitonin Gene-Related Peptide/antagonists & inhibitors , Callithrix , Coronary Vessels/drug effects , Face/blood supply , Humans , Indazoles/administration & dosage , Indazoles/chemical synthesis , Quinazolinones/administration & dosage , Quinazolinones/chemical synthesis , Rabbits , Regional Blood Flow/drug effects , Vasodilation/drug effectsABSTRACT
N-in-1 (or cassette) dosing pharmacokinetics (PK) has been used in drug discovery for rapid assessment of PK properties of new chemical entities. However, because of potential for drug-drug interactions this procedure is still controversial. This study was to retrospectively evaluate the N-in-1 dosing approach in drug discovery with an emphasis on the potential for drug-drug interactions. The systemic clearance, volume of distribution, oral bioavailability, and renal excretion of the 31 lead compounds in rats, dogs or chimpanzees were significantly correlated between the N-in-1 dosing and discrete studies with r values of 0.69, 0.91, 0.53, and 0.83 (p < 0.005 for all), respectively. PK parameters for 11 quality control compounds which were involved in 194 N-in-1 studies for screening approximately 1000 compounds had coefficient of variations of less than 70%. The intrinsic microsomal clearances generated from the N-in-1 and discrete incubations were nearly identical (r = 0.97, p < 0.0001). The intrinsic clearances of quality control compound from the N-in-1 incubations were consistent with its discrete CL(int) estimate (cv: 5.4%). Therefore, N-in-1 dosing is a useful approach in drug discovery to quickly obtain initial PK estimates. Potential drug-drug interactions that result in confounding PK estimates do not occur as frequently as expected.
Subject(s)
Cytochrome P-450 CYP3A Inhibitors , Drug Design , Drug Evaluation, Preclinical/methods , Microsomes, Liver , Pharmaceutical Preparations/administration & dosage , Pharmacokinetics , Animals , Biological Availability , Cytochrome P-450 CYP3A , Dogs , Drug Interactions , Humans , In Vitro Techniques , Male , Metabolic Clearance Rate , Microsomes, Liver/drug effects , Microsomes, Liver/enzymology , Models, Biological , Pan troglodytes , RatsABSTRACT
8-Aryl-1,3a,7,8-tetraaza-cyclopenta[a]indenes represent a novel series of high-affinity corticotropin-releasing factor-1 receptor (CRF1R) antagonists. Herein we report the synthesis and SAR around the tricyclic core and the anxiolytic activity of an orally dosed exemplary compound 9d (K(i)=8.0 nM) in a mouse canopy model.
Subject(s)
Receptors, Corticotropin-Releasing Hormone/antagonists & inhibitors , Administration, Oral , Animals , Antidepressive Agents/pharmacology , Aza Compounds/chemistry , Depression/drug therapy , Dose-Response Relationship, Drug , Indenes/chemistry , Kinetics , Mice , Mice, Inbred BALB C , Models, Chemical , Solubility , Structure-Activity Relationship , Time Factors , Water/chemistryABSTRACT
Corticotropin-releasing factor(1) (CRF(1)) antagonists may be effective in the treatment of anxiety disorders with fewer side effects compared with classic benzodiazepines. The behavioral effects of DMP904 [4-(3-pentylamino)-2,7-dimethyl-8-(2-methyl-4-methoxyphenyl)-pyrazolo-[1,5-a]-pyrimidine] and its effects on the hypothalamic-pituitary-adrenal (HPA) axis were related to its levels in plasma and estimated occupancy of central CRF(1) receptors. DMP904 (10-30 mg/kg, p.o.) and alprazolam (10 mg/kg, p.o.) increased time spent in open arms of an elevated-plus maze. In addition, acutely or chronically (14 days) administered DMP904 (1.0-30 mg/kg, p.o.) and acute alprazolam (1.0-3.0 mg/kg, p.o.) significantly reduced exit latency in the defensive withdrawal model of anxiety in rats, suggesting that tolerance may not develop to the anxiolytic-like effects of DMP904 in this model of anxiety. Acutely, DMP904 reversed the stress-induced increase in plasma corticosterone levels in defensive withdrawal at doses of 3.0 mg/kg and higher. These doses also resulted in levels of DMP904 in plasma similar to (for anxiolytic-like effects) or 4-fold higher (for effects on the HPA axis) than the in vitro IC(50) value for binding affinity at CRF(1) receptors and greater than 50% occupancy of CRF(1) receptors. Unlike alprazolam, DMP904 did not produce sedation, ataxia, or chlordiazepoxide-like subjective effects (as measured by locomotor activity, rotorod performance, and chlordiazepoxide discrimination assays, respectively) at doses at least 3-fold higher than anxiolytic-like doses. In conclusion, anxiolytic-like effects and effects on the stress-activated HPA axis of DMP904 in the defensive withdrawal model of anxiety required 50% or greater occupancy of central CRF(1) receptors. This level of CRF(1) receptor occupancy resulted in fewer motoric side effects compared with classic benzodiazepines.
Subject(s)
Anti-Anxiety Agents/pharmacology , Maze Learning/drug effects , Motor Activity/drug effects , Pyrazoles/pharmacology , Pyrimidines/pharmacology , Receptors, Corticotropin-Releasing Hormone/antagonists & inhibitors , Animals , Anti-Anxiety Agents/blood , Anti-Anxiety Agents/therapeutic use , Anxiety/drug therapy , Chlordiazepoxide/pharmacology , Corticosterone/blood , Discrimination Learning/drug effects , Male , Pyrazoles/blood , Pyrazoles/therapeutic use , Pyrimidines/blood , Pyrimidines/therapeutic use , Rats , Rats, Sprague-Dawley , Substance Withdrawal SyndromeABSTRACT
4-(1,3-Dimethoxyprop-2-ylamine)-2,7-dimethyl-8-(2,4-dichlorophenyl)-pyrazolo[1,5-a]-1,3,5-triazine (DMP696) is a highly selective and potent, nonpeptide corticotropin-releasing factor 1 (CRF(1)) antagonist. In this study, we measured in vivo CRF(1) receptor occupancy of DMP696 by using ex vivo ligand binding and quantitative autoradiography and explored the relationship of receptor occupancy with plasma and brain exposure and behavioral efficacy. In vitro affinity (IC(50)) of DMP696 to brain CRF(1) receptors measured using the brain section binding autoradiography in this study is similar to that assessed using homogenized cell membrane assays previously. The ex vivo binding assay was validated by demonstrating that potential underestimation of receptor occupancy with this procedure could be minimized by identifying an appropriate in vitro incubation time (40 min) based upon the dissociation kinetics of DMP696. Orally administrated DMP696 dose dependently occupied CRF(1) receptors in the brain, with ~60% occupancy at 3 mg/kg. In the defensive withdrawal test of anxiety, this dose of DMP696 produced approximately 50% reduction in the exit latency. The time course of plasma and brain drug levels paralleled that of receptor occupancy, with peak exposure at 90 min after dosing. The plasma-free concentration of DMP696 corresponding to 50% CRF(1) receptor occupancy (in vivo IC(50), 1.22 nM) was similar to the in vitro IC(50) (~1.0 nM). Brain concentrations of DMP696 were over 150-fold higher than the plasma-free levels. In conclusion, doses of DMP696 occupying over 50% brain CRF(1) receptors are consistent with doses producing anxiolytic efficacy in the defense withdrawal test of anxiety, and the IC(50) value estimated in vivo based on plasma-free drug concentrations is consistent with the in vitro IC(50) value.