RESUMO
6-Phenylnicotinamide (2) was previously identified as a potent TRPV1 antagonist with activity in an in vivo model of inflammatory pain. Optimization of this lead through modification of both the biaryl and heteroaryl components has resulted in the discovery of 6-(4-fluorophenyl)-2-methyl-N-(2-methylbenzothiazol-5-yl)nicotinamide (32; SB-782443) which possesses an excellent overall profile and has been progressed into pre-clinical development.
Assuntos
Benzotiazóis/síntese química , Química Farmacêutica/métodos , Niacinamida/análogos & derivados , Niacinamida/síntese química , Canais de Cátion TRPV/antagonistas & inibidores , Canais de Cátion TRPV/química , Administração Oral , Animais , Benzotiazóis/farmacologia , Capsaicina/química , Linhagem Celular , Desenho de Fármacos , Cobaias , Humanos , Inflamação , Concentração Inibidora 50 , Modelos Químicos , Niacinamida/química , Niacinamida/farmacologia , RatosRESUMO
Vanilloid receptor-1 (TRPV1) is a nonselective cation channel, predominantly expressed by sensory neurons, which plays a key role in the detection of noxious painful stimuli such as capsaicin, acid, and heat. TRPV1 antagonists may represent novel therapeutic agents for the treatment of a range of conditions including chronic pain, migraine, and gastrointestinal disorders. Here we describe the in vitro pharmacology of N-(2-bromophenyl)-N'-[((R)-1-(5-trifluoromethyl-2-pyridyl)pyrrolidin-3-yl)]urea (SB-705498), a novel TRPV1 antagonist identified by lead optimization of N-(2-bromophenyl)-N'-[2-[ethyl(3-methylphenyl)amino]ethyl]urea (SB-452533), which has now entered clinical trials. Using a Ca(2+)-based fluorometric imaging plate reader (FLIPR) assay, SB-705498 was shown to be a potent competitive antagonist of the capsaicin-mediated activation of the human TRPV1 receptor (pK(i) = 7.6) with activity at rat (pK(i) = 7.5) and guinea pig (pK(i) = 7.3) orthologs. Whole-cell patch-clamp electrophysiology was used to confirm and extend these findings, demonstrating that SB-705498 can potently inhibit the multiple modes of receptor activation that may be relevant to the pathophysiological role of TRPV1 in vivo: SB-705498 caused rapid and reversible inhibition of the capsaicin (IC(50) = 3 nM)-, acid (pH 5.3)-, or heat (50 degrees C; IC(50) = 6 nM)-mediated activation of human TRPV1 (at -70 mV). Interestingly, SB-705498 also showed a degree of voltage dependence, suggesting an effective enhancement of antagonist action at negative potentials such as those that might be encountered in neurons in vivo. The selectivity of SB-705498 was defined by broad receptor profiling and other cellular assays in which it showed little or no activity versus a wide range of ion channels, receptors, and enzymes. SB-705498 therefore represents a potent and selective multimodal TRPV1 antagonist, a pharmacological profile that has contributed to its definition as a suitable drug candidate for clinical development.
Assuntos
Ácidos/farmacologia , Capsaicina/farmacologia , Temperatura Alta , Pirrolidinas/farmacologia , Canais de Cátion TRPV/antagonistas & inibidores , Ureia/análogos & derivados , Animais , Ligação Competitiva/efeitos dos fármacos , Sinalização do Cálcio/efeitos dos fármacos , Linhagem Celular , Células Cultivadas , Relação Dose-Resposta a Droga , Eletrofisiologia , Cobaias , Humanos , Concentração de Íons de Hidrogênio , Potenciais da Membrana/efeitos dos fármacos , Estrutura Molecular , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/fisiologia , Técnicas de Patch-Clamp , Pirrolidinas/química , Ratos , Canais de Cátion TRPV/genética , Canais de Cátion TRPV/fisiologia , Transfecção , Ureia/química , Ureia/farmacologiaRESUMO
Small molecule antagonists of the vanilloid receptor TRPV1 (also known as VR1) are disclosed. Pyrrolidinyl ureas such as 8 and 15 (SB-705498) emerged as lead compounds following optimisation of the previously described urea SB-452533. Pharmacological studies using electrophysiological and FLIPR-Ca2+-based assays showed that compounds such as 8 and 15 were potent antagonists versus the multiple chemical and physical modes of TRPV1 activation (namely capsaicin, acid and noxious heat). Furthermore, 15 possessed suitable developability properties to enable progression of this compound into in vivo studies and subsequently clinical development.
Assuntos
Pirrolidinas/síntese química , Pirrolidinas/farmacologia , Canais de Cátion TRPV/antagonistas & inibidores , Ureia/análogos & derivados , Administração Oral , Animais , Capsaicina/farmacologia , Linhagem Celular , Desenho de Fármacos , Cobaias , Humanos , Estrutura Molecular , Pirrolidinas/administração & dosagem , Pirrolidinas/química , Ratos , Relação Estrutura-Atividade , Canais de Cátion TRPV/metabolismo , Ureia/administração & dosagem , Ureia/síntese química , Ureia/química , Ureia/farmacologiaRESUMO
Starting from the high throughput screening hit (3), novel N-tetrahydroquinolinyl, N-quinolinyl and N-isoquinolinyl carboxamides have been identified as potent antagonists of the ion channel TRPV1. The N-quinolinylnicotinamide (46) showed excellent potency at human, guinea pig and rat TRPV1, a favourable in vitro DMPK profile and activity in an in vivo model of inflammatory pain.
Assuntos
Benzamidas/química , Benzamidas/farmacologia , Isoquinolinas/química , Isoquinolinas/farmacologia , Quinolinas/química , Quinolinas/farmacologia , Canais de Cátion TRPV/antagonistas & inibidores , Animais , Benzamidas/síntese química , Capsaicina/farmacologia , Cobaias , Humanos , Isoquinolinas/síntese química , Fígado/efeitos dos fármacos , Fígado/metabolismo , Estrutura Molecular , Quinolinas/síntese química , Ratos , Relação Estrutura-Atividade , Canais de Cátion TRPV/metabolismoRESUMO
Starting from a high throughput screening hit, a series of 3,4-dihydro-2H-benzoxazinones has been identified with both high affinity for the 5-HT(1A) receptor and potent 5-HT reuptake inhibitory activity. The 5-(2-methyl)quinolinyloxy derivative combined high 5-HT(1A/1B/1D) receptor affinities with low intrinsic activity and potent inhibition of the 5-HT reuptake site (pK(i)8.2). This compound also had good oral bioavailability and brain penetration in the rat.
Assuntos
Benzoxazinas/síntese química , Inibidores Seletivos de Recaptação de Serotonina/síntese química , Antagonistas do Receptor 5-HT1 de Serotonina , Animais , Benzoxazinas/farmacologia , Disponibilidade Biológica , Encéfalo/metabolismo , Linhagem Celular , Estabilidade de Medicamentos , Humanos , Ensaio Radioligante , Ratos , Inibidores Seletivos de Recaptação de Serotonina/farmacologia , Relação Estrutura-Atividade , Sinaptossomos/metabolismoRESUMO
BACKGROUND: SB-236057 is a potent skeletal teratogen in rodents and rabbits, producing axial and posterior somite malformations in cultured rat embryos. The compound shares some structural similarity to cyclopamine. METHODS: M13 phage display was used to identify amino acid motifs with binding affinity to SB-236057. A 10 microM SB-236057 solution was administered to cultured day 9 postcoitus rat embryos and real-time PCR was conducted at 6 hr posttreatment to evaluate early transcriptional response of axial development genes. Whole-mount in situ hybridization of selected transcripts was conducted on embryos at 48 hr post-compound administration. The rat-enhancer of split protein 1 (r-esp1) expression-functional characterization was done by transcriptional expression and morpholino antisense approaches. RESULTS: We identified several amino acid motifs that had high binding affinity to SB-236057-biotin conjugates, one with 100% sequence homology to a region of r-esp1, one of the Groucho homologs transcribed by the enhancer of split complex (En[spl]C). SB-236057 repressed expression of r-esp1 and members of the Notch-En[spl]C pathway. Goosecoid and HNF3-beta, both suspected to associate with Groucho proteins, were also responsive, although expression of another putative binding protein, engrailed-1 (en-1), and other en-1 pathway members was not affected. R-esp1 mRNA was localized along the axis and antisense inhibition produced similar somite malformations as SB-236057 did. At 48 hr post-SB-236057 or post-r-esp1 antisense administration, affected embryos demonstrated unchanged sonic hedgehog (shh) expression, however HNF3-beta expression was either absent, altered, or reduced. CONCLUSIONS: We present experimental evidence that the mechanism of SB-236057 teratogenicity includes transcriptional alterations to the Notch1-En[spl] pathway. In addition, alterations in HNF3-beta expression were similar to those induced by cyclopamine. The relationships between r-esp1 with Notch1 and shh signaling pathways and potential mechanisms of SB-236057 teratogenicity are also discussed.
Assuntos
Padronização Corporal/efeitos dos fármacos , Indóis/toxicidade , Piridinas/toxicidade , Antagonistas da Serotonina/toxicidade , Teratogênicos/toxicidade , Animais , Bacteriófago M13/genética , Sequência de Bases , Primers do DNA , Proteínas de Ligação a DNA/genética , Feminino , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Fator 3-beta Nuclear de Hepatócito , Hibridização In Situ , Microscopia Confocal , Proteínas Nucleares/genética , Gravidez , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/genéticaRESUMO
Small molecule antagonists of the vanilloid receptor 1 (TRPV1, also known as VR1) are disclosed. Ureas such as 5 (SB-452533) were used to explore the structure activity relationship with several potent analogues identified. Pharmacological studies using electrophysiological and FLIPR Ca(2+) based assays showed compound 5 was an antagonist versus capsaicin, noxious heat and acid mediated activation of TRPV1. Study of a quaternary salt of 5 supports a mode of action in which compounds from this series cause inhibition via an extracellularly accessible binding site on the TRPV1 receptor.