RESUMO
Structure-based led optimisation of orally active reversible Methionine Aminopeptidase-2 (MetAP-2) inhibitors utilising a 'molecular budget' medicinal chemistry strategy is described. The key physicochemical parameters of target molecules (cLogP, molecular size and H-bond donor count) were monitored through straightforward and intuitive use of atom count and distribution. The balance between structure-based design and an awareness of the physicochemical properties of the compounds synthesised enabled the rapid identification of a potent molecule with good oral pharmacokinetic (PK) characteristics by making fewer, higher quality compounds. The resulting candidate quality molecule was validated in a mechanistic cellular assay and a rodent secondary immunisation model.
Assuntos
Inibidores Enzimáticos/farmacologia , Indóis/farmacologia , Metionil Aminopeptidases/antagonistas & inibidores , Química Farmacêutica , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Indóis/síntese química , Indóis/química , Metionil Aminopeptidases/metabolismo , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
The bromodomain and extraterminal (BET) protein BRD2-4 inhibitors hold therapeutic promise in preclinical models of hematologic malignancies. However, translation of these data to molecules suitable for clinical development has yet to be accomplished. Herein we expand the mechanistic understanding of BET inhibitors in multiple myeloma by using the chemical probe molecule I-BET151. I-BET151 induces apoptosis and exerts strong antiproliferative effect in vitro and in vivo. This is associated with contrasting effects on oncogenic MYC and HEXIM1, an inhibitor of the transcriptional activator P-TEFb. I-BET151 causes transcriptional repression of MYC and MYC-dependent programs by abrogating recruitment to the chromatin of the P-TEFb component CDK9 in a BRD2-4-dependent manner. In contrast, transcriptional upregulation of HEXIM1 is BRD2-4 independent. Finally, preclinical studies show that I-BET762 has a favorable pharmacologic profile as an oral agent and that it inhibits myeloma cell proliferation, resulting in survival advantage in a systemic myeloma xenograft model. These data provide a strong rationale for extending the clinical testing of the novel antimyeloma agent I-BET762 and reveal insights into biologic pathways required for myeloma cell proliferation.
Assuntos
Antineoplásicos/uso terapêutico , Benzodiazepinas/uso terapêutico , Compostos Heterocíclicos de 4 ou mais Anéis/uso terapêutico , Mieloma Múltiplo/tratamento farmacológico , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Benzodiazepinas/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Humanos , Camundongos , Mieloma Múltiplo/genética , Mieloma Múltiplo/patologia , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas de Ligação a RNA/genética , Fatores de Transcrição , Ativação Transcricional/efeitos dos fármacos , Células Tumorais CultivadasRESUMO
A series of α7 nicotinic acetylcholine receptor full-agonists with a 1,3,4-oxadiazol-2-amine core has been discovered. Systematic exploration of the structure-activity relationships for both α7 potency and selectivity with respect to interaction with the hERG channel are described. Further profiling led to the identification of compound 22, a potent full agonist showing efficacy in the novel object recognition model of cognition enhancement.
Assuntos
Cognição/efeitos dos fármacos , Agonistas Nicotínicos/farmacologia , Receptores Nicotínicos/efeitos dos fármacos , Animais , Cães , Agonistas Nicotínicos/química , Receptor Nicotínico de Acetilcolina alfa7RESUMO
A novel series of quinoline isoxazole BET family bromodomain inhibitors are discussed. Crystallography is used to illustrate binding modes and rationalize their SAR. One member, I-BET151 (GSK1210151A), shows good oral bioavailability in both the rat and minipig as well as demonstrating efficient suppression of bacterial induced inflammation and sepsis in a murine in vivo endotoxaemia model.
Assuntos
Compostos Heterocíclicos de 4 ou mais Anéis/química , Isoxazóis/síntese química , Proteínas do Tecido Nervoso/antagonistas & inibidores , Quinolinas/síntese química , Animais , Sítios de Ligação , Cristalografia por Raios X , Cobaias , Compostos Heterocíclicos de 4 ou mais Anéis/metabolismo , Inflamação/tratamento farmacológico , Isoxazóis/química , Isoxazóis/farmacologia , Camundongos , Modelos Moleculares , Ligação Proteica/efeitos dos fármacos , Quinolinas/química , Quinolinas/farmacologia , RatosRESUMO
A series of α7 nicotinic acetylcholine receptor full agonists with a 1,3,4-oxadiazol-2-amine core has been discovered. Early lead 1 was found to have a limited therapeutic index with respect to its potential for cardiovascular side effects. Further optimisation of this series led to the identification of 22 a potent full agonist showing efficacy at a dose of 0.1mg/kg in the novel object recognition model of cognition enhancement. Comparison of 1 with 22 demonstrated the latter to have an improved oral pharmacokinetic profile and cardiovascular therapeutic index.
Assuntos
Cognição/efeitos dos fármacos , Agonistas Nicotínicos/farmacologia , Receptores Nicotínicos/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Coelhos , Receptores Nicotínicos/química , Receptor Nicotínico de Acetilcolina alfa7RESUMO
Through regulation of the epigenome, the bromodomain and extra terminal (BET) family of proteins represent important therapeutic targets for the treatment of human disease. Through mimicking the endogenous N-acetyl-lysine group and disrupting the protein-protein interaction between histone tails and the bromodomain, several small molecule pan-BET inhibitors have progressed to oncology clinical trials. This work describes the medicinal chemistry strategy and execution to deliver an orally bioavailable tetrahydroquinoline (THQ) pan-BET candidate. Critical to the success of this endeavor was a potency agnostic analysis of a data set of 1999 THQ BET inhibitors within the GSK collection which enabled identification of appropriate lipophilicity space to deliver compounds with a higher probability of desired oral candidate quality properties. SAR knowledge was leveraged via Free-Wilson analysis within this design space to identify a small group of targets which ultimately delivered I-BET567 (27), a pan-BET candidate inhibitor that demonstrated efficacy in mouse models of oncology and inflammation.
Assuntos
Aminoquinolinas/química , Desenho de Fármacos , Proteínas/metabolismo , Administração Oral , Aminoquinolinas/metabolismo , Aminoquinolinas/farmacocinética , Aminoquinolinas/uso terapêutico , Animais , Benzoatos/química , Benzoatos/metabolismo , Sítios de Ligação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Cães , Meia-Vida , Humanos , Masculino , Camundongos , Conformação Molecular , Simulação de Dinâmica Molecular , Neoplasias/tratamento farmacológico , Proteínas/antagonistas & inibidores , Ratos , Relação Estrutura-AtividadeRESUMO
The functions of the bromodomain and extra terminal (BET) family of proteins have been implicated in a wide range of diseases, particularly in the oncology and immuno-inflammatory areas, and several inhibitors are under investigation in the clinic. To mitigate the risk of attrition of these compounds due to structurally related toxicity findings, additional molecules from distinct chemical series were required. Here we describe the structure- and property-based optimization of the in vivo tool molecule I-BET151 toward I-BET282E, a molecule with properties suitable for progression into clinical studies.
Assuntos
Anti-Inflamatórios/uso terapêutico , Artrite/tratamento farmacológico , Imidazóis/uso terapêutico , Proteínas Nucleares/antagonistas & inibidores , Quinolinas/uso terapêutico , Fatores de Transcrição/antagonistas & inibidores , Animais , Anti-Inflamatórios/síntese química , Anti-Inflamatórios/metabolismo , Artrite/induzido quimicamente , Colágeno , Cristalografia por Raios X , Cães , Feminino , Imidazóis/síntese química , Imidazóis/metabolismo , Masculino , Camundongos , Estrutura Molecular , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Ligação Proteica , Domínios Proteicos , Quinolinas/síntese química , Quinolinas/metabolismo , Ratos Endogâmicos Lew , Ratos Wistar , Relação Estrutura-Atividade , Fatores de Transcrição/química , Fatores de Transcrição/metabolismoRESUMO
Inhibition of the aspartyl protease BACE-1 has the potential to deliver a disease-modifying therapy for Alzheimer's disease. Herein, is described a series of potent inhibitors based on an hydroxyethylamine (HEA) transition state mimetic template. These inhibitors interact with the non prime side of the enzyme using a novel edge-to-face interaction with Arg-296.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Arginina/química , Etilaminas/química , Inibidores de Proteases/química , Doença de Alzheimer/tratamento farmacológico , Secretases da Proteína Precursora do Amiloide/química , Secretases da Proteína Precursora do Amiloide/metabolismo , Animais , Sítios de Ligação , Simulação por Computador , Cristalografia por Raios X , Etilaminas/síntese química , Etilaminas/uso terapêutico , Inibidores de Proteases/síntese química , Inibidores de Proteases/uso terapêutico , Ratos , Relação Estrutura-AtividadeRESUMO
The bromodomain and extraterminal domain (BET) family of epigenetic regulators comprises four proteins (BRD2, BRD3, BRD4, BRDT), each containing tandem bromodomains. To date, small molecule inhibitors of these proteins typically bind all eight bromodomains of the family with similar affinity, resulting in a diverse range of biological effects. To enable further understanding of the broad phenotype characteristic of pan-BET inhibition, the development of inhibitors selective for individual, or sets of, bromodomains within the family is required. In this regard, we report the discovery of a potent probe molecule possessing up to 150-fold selectivity for the N-terminal bromodomains (BD1s) over the C-terminal bromodomains (BD2s) of the BETs. Guided by structural information, a specific amino acid difference between BD1 and BD2 domains was targeted for selective interaction with chemical functionality appended to the previously developed I-BET151 scaffold. Data presented herein demonstrate that selective inhibition of BD1 domains is sufficient to drive anti-inflammatory and antiproliferative effects.
Assuntos
Anti-Inflamatórios/química , Proteínas de Ciclo Celular/antagonistas & inibidores , Desenho de Fármacos , Fatores de Transcrição/antagonistas & inibidores , Animais , Anti-Inflamatórios/metabolismo , Anti-Inflamatórios/farmacologia , Sítios de Ligação , Proteínas de Ciclo Celular/classificação , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Citocinas/metabolismo , Meia-Vida , Humanos , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Masculino , Camundongos , Simulação de Dinâmica Molecular , Filogenia , Domínios Proteicos , Quinolonas/química , Quinolonas/metabolismo , Quinolonas/farmacologia , Fatores de Transcrição/classificação , Fatores de Transcrição/metabolismoRESUMO
Inhibition of the aspartyl protease BACE-1 has the potential to deliver a disease-modifying therapy for Alzheimer's disease. We have recently disclosed a series of transition-state mimetic BACE-1 inhibitors showing nanomolar potency in cell-based assays. Amongst them, GSK188909 (compound 2) had favorable pharmacokinetics and was the first orally bioavailable inhibitor reported to demonstrate brain amyloid lowering in an animal model. In this Letter, we describe the reasons that led us to favor a second generation of inhibitors for further in vivo studies.
Assuntos
Ácido Aspártico Endopeptidases/antagonistas & inibidores , Inibidores de Proteases/química , Tiazinas/química , Administração Oral , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/metabolismo , Animais , Ácido Aspártico Endopeptidases/metabolismo , Sítios de Ligação , Simulação por Computador , Etilaminas/síntese química , Etilaminas/química , Etilaminas/farmacologia , Humanos , Camundongos , Inibidores de Proteases/farmacocinética , Ratos , Relação Estrutura-Atividade , Tiazinas/síntese química , Tiazinas/farmacocinéticaRESUMO
Our first generation of hydroxyethylamine BACE-1 inhibitors proved unlikely to provide molecules that would lower amyloid in an animal model at low oral doses. This observation led us to the discovery of a second generation of inhibitors having nanomolar activity in a cell-based assay and with the potential for improved pharmacokinetic profiles. In this Letter, we describe our successful strategy for the optimization of oral bioavailability and also give insights into the design of compounds with the potential for improved brain penetration.
Assuntos
Ácido Aspártico Endopeptidases/antagonistas & inibidores , Etilaminas/química , Inibidores de Proteases/química , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Ácido Aspártico Endopeptidases/metabolismo , Disponibilidade Biológica , Cães , Etilaminas/síntese química , Etilaminas/farmacocinética , Camundongos , Camundongos Knockout , Inibidores de Proteases/síntese química , Inibidores de Proteases/farmacocinética , Ratos , Relação Estrutura-AtividadeRESUMO
BACE-1 inhibition has the potential to provide a disease-modifying therapy for the treatment of Alzheimer's disease. Optimization of a first generation of BACE-1 inhibitors led to the discovery of novel hydroxyethylamines (HEAs) bearing a tricyclic nonprime side. These derivatives have nanomolar cell potency and are orally bioavailable.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Benzotiadiazinas/síntese química , Óxidos S-Cíclicos/síntese química , Etilaminas/síntese química , Administração Oral , Animais , Benzotiadiazinas/farmacocinética , Benzotiadiazinas/farmacologia , Disponibilidade Biológica , Óxidos S-Cíclicos/farmacocinética , Óxidos S-Cíclicos/farmacologia , Cães , Etilaminas/farmacocinética , Etilaminas/farmacologia , Modelos Moleculares , Ratos , Relação Estrutura-AtividadeRESUMO
We describe the discovery of a series of pyrazole amide EP(1) receptor antagonists with good aqueous solubility and CNS penetration. In order to achieve solubility we investigated the incorporation of a basic group in the region of the molecule previously occupied by a carboxylic acid, which was known to be a key element of the pharmacophore. This study led to the identification of compounds such as 4h, 4j and 10b which demonstrated brain-to-blood ratios of 0.8:1-2.0:1 in addition to good solubility and metabolic stability.
Assuntos
Encéfalo/efeitos dos fármacos , Sistema Nervoso Central/efeitos dos fármacos , Pirazóis/química , Receptores de Prostaglandina E/antagonistas & inibidores , Amidas/química , Ácidos Carboxílicos/química , Química Farmacêutica/métodos , Desenho de Fármacos , Humanos , Concentração Inibidora 50 , Isoquinolinas/química , Modelos Químicos , Estrutura Molecular , Receptores de Prostaglandina E Subtipo EP1 , Solubilidade , Relação Estrutura-AtividadeRESUMO
Non-alcoholic fatty liver disease (NAFLD) is a leading form of chronic liver disease with large unmet need. Non-alcoholic steatohepatitis (NASH), a progressive variant of NAFLD, can lead to fibrosis, cirrhosis, and hepatocellular carcinoma. To identify potential new therapeutics for NASH, we used a computational approach based on Connectivity Map (CMAP) analysis, which pointed us to bromodomain and extra-terminal motif (BET) inhibitors for treating NASH. To experimentally validate this hypothesis, we tested a small-molecule inhibitor of the BET family of proteins, GSK1210151A (I-BET151), in the STAM mouse NASH model at two different dosing timepoints (onset of NASH and progression to fibrosis). I-BET151 decreased the non-alcoholic fatty liver disease activity score (NAS), a clinical endpoint for assessing the severity of NASH, as well as progression of liver fibrosis and interferon-γ expression. Transcriptional characterization of these mice through RNA-sequencing was consistent with predictions from the CMAP analysis of a human NASH signature and pointed to alterations in molecular mechanisms related to interferon signaling and cholesterol biosynthesis, as well as reversal of gene expression patterns linked to fibrotic markers. Altogether, these results suggest that inhibition of BET proteins may present a novel therapeutic opportunity in the treatment of NASH and liver fibrosis.
Assuntos
Biologia Computacional/métodos , Redes Reguladoras de Genes/efeitos dos fármacos , Compostos Heterocíclicos de 4 ou mais Anéis/administração & dosagem , Cirrose Hepática/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Animais , Colesterol/biossíntese , Modelos Animais de Doenças , Progressão da Doença , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Humanos , Interferon gama/metabolismo , Cirrose Hepática/genética , Cirrose Hepática/imunologia , Camundongos , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/imunologia , Análise de Sequência de RNA , Índice de Gravidade de DoençaRESUMO
The objective of this study was to establish the optimal blood concentrations of the potent P-glycoprotein (P-gp) inhibitor GF120918 (Elacridar) required to achieve maximal knockout of this efflux transporter in the blood-brain barrier (BBB) of mice, rats, and guinea pigs. Genetic mdr1a/b(-/-) knockout mice and "chemical" P-gp knockout mice, rats, and guinea pigs, generated by 24 h continuous infusion of GF120918, were used to investigate the effects of P-gp modulation on the brain penetration of SB-487946. Genetic mdr1a/b(-/-) knockout mice demonstrated a >70-fold increase in brain:blood ratio of SB-487946 compared to mdr1a/b(+/+) wild-type mice. There was a similar increase in SB-487946 brain:blood ratio in GF120918-treated mice (ca. >67-fold) and rats (ca. 95-fold) but a significantly smaller increase (ca. 10-fold) in guinea pigs treated with GF120918. An appreciable difference was found in the BBB functional effect of P-gp efflux in rodents. GF120918 blood EC90 in mice and rats were similar however, the EC90 in guinea pigs was ca. 10-fold higher, suggesting a species difference in the activity of P-gp at the BBB in some rodents. This study establishes the optimal blood concentrations of GF120918 in relation to SB-487946, to achieve chemically induced P-gp knockout in rodents.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Barreira Hematoencefálica/fisiologia , Acridinas/farmacocinética , Animais , Animais Geneticamente Modificados , Cromatografia Líquida de Alta Pressão , Relação Dose-Resposta a Droga , Genes MDR/genética , Cobaias , Masculino , Espectrometria de Massas , Camundongos , Camundongos Knockout , Ratos , Ratos Sprague-Dawley , Especificidade da Espécie , Tetra-Hidroisoquinolinas/farmacocinéticaRESUMO
Through their function as epigenetic readers of the histone code, the BET family of bromodomain-containing proteins regulate expression of multiple genes of therapeutic relevance, including those involved in tumor cell growth and inflammation. BET bromodomain inhibitors have profound antiproliferative and anti-inflammatory effects which translate into efficacy in oncology and inflammation models, and the first compounds have now progressed into clinical trials. The exciting biology of the BETs has led to great interest in the discovery of novel inhibitor classes. Here we describe the identification of a novel tetrahydroquinoline series through up-regulation of apolipoprotein A1 and the optimization into potent compounds active in murine models of septic shock and neuroblastoma. At the molecular level, these effects are produced by inhibition of BET bromodomains. X-ray crystallography reveals the interactions explaining the structure-activity relationships of binding. The resulting lead molecule, I-BET726, represents a new, potent, and selective class of tetrahydroquinoline-based BET inhibitors.
Assuntos
Aminoquinolinas/síntese química , Anti-Inflamatórios/síntese química , Apolipoproteína A-I/metabolismo , Benzoatos/síntese química , Proteínas Nucleares/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Quinolinas/síntese química , Fatores de Transcrição/antagonistas & inibidores , Aminoquinolinas/farmacocinética , Aminoquinolinas/farmacologia , Animais , Anti-Inflamatórios/farmacocinética , Anti-Inflamatórios/farmacologia , Benzoatos/farmacocinética , Benzoatos/farmacologia , Proteínas de Ciclo Celular , Descoberta de Drogas , Humanos , Camundongos , Quinolinas/farmacocinética , Quinolinas/farmacologia , Relação Estrutura-AtividadeRESUMO
The bromo and extra C-terminal domain (BET) family of bromodomains are involved in binding epigenetic marks on histone proteins, more specifically acetylated lysine residues. This paper describes the discovery and structure-activity relationships (SAR) of potent benzodiazepine inhibitors that disrupt the function of the BET family of bromodomains (BRD2, BRD3, and BRD4). This work has yielded a potent, selective compound I-BET762 that is now under evaluation in a phase I/II clinical trial for nuclear protein in testis (NUT) midline carcinoma and other cancers.
Assuntos
Antineoplásicos/farmacologia , Benzodiazepinas/farmacologia , Proteínas Nucleares/antagonistas & inibidores , Fatores de Transcrição/antagonistas & inibidores , Animais , Anti-Inflamatórios/síntese química , Anti-Inflamatórios/farmacocinética , Anti-Inflamatórios/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/farmacocinética , Apolipoproteína A-I/biossíntese , Benzodiazepinas/síntese química , Benzodiazepinas/farmacocinética , Proteínas de Ciclo Celular , Cães , Epigênese Genética , Humanos , Macaca fascicularis , Camundongos , Modelos Moleculares , Permeabilidade , Estrutura Terciária de Proteína , Ratos , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Generation and deposition of the amyloid beta (Abeta) peptide following proteolytic processing of the amyloid precursor protein (APP) by BACE-1 and gamma-secretase is central to the aetiology of Alzheimer's disease. Consequently, inhibition of BACE-1, a rate-limiting enzyme in the production of Abeta, is an attractive therapeutic approach for the treatment of Alzheimer's disease. We have designed a selective non-peptidic BACE-1 inhibitor, GSK188909, that potently inhibits beta-cleavage of APP and reduces levels of secreted and intracellular Abeta in SHSY5Y cells expressing APP. In addition, we demonstrate that this compound can effectively lower brain Abeta in vivo. In APP transgenic mice, acute oral administration of GSK188909 in the presence of a p-glycoprotein inhibitor to markedly enhance the exposure of GSK188909 in the brain decreases beta-cleavage of APP and results in a significant reduction in the level of Abeta40 and Abeta42 in the brain. Encouragingly, subchronic dosing of GSK188909 in the absence of a p-glycoprotein inhibitor also lowers brain Abeta. This pivotal first report of central Abeta lowering, following oral administration of a BACE-1 inhibitor, supports the development of BACE-1 inhibitors for the treatment of Alzheimer's disease.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/biossíntese , Precursor de Proteína beta-Amiloide/metabolismo , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Encéfalo/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Tiazinas/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Administração Oral , Doença de Alzheimer/metabolismo , Doença de Alzheimer/fisiopatologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/química , Animais , Ácido Aspártico Endopeptidases/metabolismo , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Linhagem Celular Tumoral , Modelos Animais de Doenças , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/fisiologia , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/uso terapêutico , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Peptídeos/metabolismo , Tiazinas/síntese química , Tiazinas/uso terapêutico , Resultado do TratamentoRESUMO
This work examines the inter-relationship between the unbound drug fractions in blood and brain homogenate, passive membrane permeability, P-glycoprotein (Pgp) efflux ratio, and log octanol/water partition coefficients (cLogP) in determining the extent of central nervous system (CNS) penetration observed in vivo. The present results demonstrate that compounds often considered to be Pgp substrates in rodents (efflux ratio greater than 5 in multidrug resistant Madin-Darby canine kidney cells) with poor passive permeability may still exhibit reasonable CNS penetration in vivo; i.e., where the unbound fractions and nonspecific tissue binding act as a compensating force. In these instances, the efflux ratio and in vitro blood-brain partition ratio may be used to predict the in vivo blood-brain ratio. This relationship may be extended to account for the differences in CNS penetration observed in vivo between mdr1a/b wild type and knockout mice. In some instances, cross-species differences that might initially seem to be related to differing transporter expression can be rationalized from knowledge of unbound fractions alone. The results presented in this article suggest that the information exists to provide a coherent picture of the nature of CNS penetration in the drug discovery setting, allowing the focus to be shifted away from understanding CNS penetration toward the more important aspect of understanding CNS efficacy.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Barreira Hematoencefálica , Encéfalo/metabolismo , Animais , Diálise , Cães , Masculino , Camundongos , Permeabilidade , Ratos , Solubilidade , Especificidade da EspécieRESUMO
The novel 8-piperazinyl-2,3-dihydropyrroloisoquinoline template was synthesized in nine steps. The template was N-substituted to give a series of compounds showing binding to human cloned 5-HT1A, 5-HT1B and 5-HT1D receptors with pKi's greater than 9 and selectivities up to 1000-fold against other serotonin, dopamine and adrenergic receptors. Several compounds were shown to possess weak partial agonist activity in cloned receptors, which translated to antagonism in in vitro studies.