RESUMO
Physical instability of aqueous drug solutions, such as precipitation upon storage, has so far been difficult to predict or model. Understanding the molecular basis of such phenomena can help mitigate by influencing the product composition and by providing a mechanistic basis of experimental and in silico investigations. In this study, inconsistent precipitation of a model drug, GNE-01 in aqueous solutions was investigated. Chromatographic analyses of the drug solution that showed precipitation upon storage versus the one that did not indicate lack of covalent modification or degradation of the drug, suggesting that the precipitation was a physical phenomenon. Molecular level investigations were conducted using surface tension measurement and nuclear magnetic resonance (NMR) spectroscopy. The studies revealed self-association of the weakly basic drug in solution at slightly acidic pH values which was strengthened by the presence of polyionic excipients. The role of polyionic excipients in facilitating drug precipitation on storage was indicative of shifting solution equilibria in favor of a lower solubility drug-excipient complex. This study highlighted the importance of molecular understanding in mitigating difficult to predict physical instability of self-associating drugs in solution.
Assuntos
Excipientes , Água , Excipientes/química , Solubilidade , Tensão SuperficialRESUMO
We describe the structural optimization of a lead compound 1 that exhibits dual inhibitory activities against FLT3 and CDK4. A series of pyrido[4',3':4,5]pyrrolo[2,3-d]pyrimidine derivatives was synthesized, and SAR analysis, using cell-based assays, led to the discovery of 28 (AMG 925), a potent and orally bioavailable dual inhibitor of CDK4 and FLT3, including many FLT3 mutants reported to date. Compound 28 inhibits the proliferation of a panel of human tumor cell lines including Colo205 (Rb(+)) and U937 (FLT3(WT)) and induced cell death in MOLM13 (FLT3(ITD)) and even in MOLM13 (FLT3(ITD, D835Y)), which exhibits resistance to a number of FLT3 inhibitors currently under clinical development. At well-tolerated doses, compound 28 leads to significant growth inhibition of MOLM13 xenografts in nude mice, and the activity correlates with inhibition of STAT5 and Rb phosphorylation.
Assuntos
Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Compostos Heterocíclicos com 3 Anéis/síntese química , Naftiridinas/síntese química , Inibidores de Proteínas Quinases/síntese química , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Animais , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Citocromo P-450 CYP3A , Inibidores do Citocromo P-450 CYP3A , Cães , Descoberta de Drogas , Compostos Heterocíclicos com 3 Anéis/farmacologia , Humanos , Macaca fascicularis , Naftiridinas/farmacologia , Inibidores de Proteínas Quinases/farmacocinética , Inibidores de Proteínas Quinases/farmacologia , Ratos , Relação Estrutura-Atividade , Células U937 , Tirosina Quinase 3 Semelhante a fms/genéticaRESUMO
Acute myeloid leukemia (AML) remains a serious unmet medical need. Despite high remission rates with chemotherapy standard-of-care treatment, the disease eventually relapses in a major proportion of patients. Activating Fms-like tyrosine kinase 3 (FLT3) mutations are found in approximately 30% of patients with AML. Targeting FLT3 receptor tyrosine kinase has shown encouraging results in treating FLT3-mutated AML. Responses, however, are not sustained and acquired resistance has been a clinical challenge. Treatment options to overcome resistance are currently the focus of research. We report here the preclinical evaluation of AMG 925, a potent, selective, and bioavailable FLT3/cyclin-dependent kinase 4 (CDK4) dual kinase inhibitor. AMG 925 inhibited AML xenograft tumor growth by 96% to 99% without significant body weight loss. The antitumor activity of AMG 925 correlated with the inhibition of STAT5 and RB phosphorylation, the pharmacodynamic markers for inhibition of FLT3 and CDK4, respectively. In addition, AMG 925 was also found to inhibit FLT3 mutants (e.g., D835Y) that are resistant to the current FLT3 inhibitors (e.g., AC220 and sorafenib). CDK4 is a cyclin D-dependent kinase that plays an essential central role in regulating cell proliferation in response to external growth signals. A critical role of the CDK4-RB pathway in cancer development has been well established. CDK4-specific inhibitors are being developed for treating RB-positive cancer. AMG 925, which combines inhibition of two kinases essential for proliferation and survival of FLT3-mutated AML cells, may improve and prolong clinical responses.
Assuntos
Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Compostos Heterocíclicos com 3 Anéis/administração & dosagem , Leucemia Mieloide Aguda/tratamento farmacológico , Naftiridinas/administração & dosagem , Inibidores de Proteínas Quinases/administração & dosagem , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Animais , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Compostos Heterocíclicos com 3 Anéis/farmacocinética , Compostos Heterocíclicos com 3 Anéis/uso terapêutico , Humanos , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Nus , Naftiridinas/farmacocinética , Naftiridinas/uso terapêutico , Neoplasias Experimentais , Niacinamida/análogos & derivados , Niacinamida/farmacologia , Compostos de Fenilureia/farmacologia , Piperazinas/farmacologia , Inibidores de Proteínas Quinases/farmacocinética , Piridinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Sorafenibe , Células U937 , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Structure-based rational design led to the discovery of novel inhibitors of the MDM2-p53 protein-protein interaction. The affinity of these compounds for MDM2 was improved through conformational control of both the piperidinone ring and the appended N-alkyl substituent. Optimization afforded 29 (AM-8553), a potent and selective MDM2 inhibitor with excellent pharmacokinetic properties and in vivo efficacy.
Assuntos
Acetatos/síntese química , Antineoplásicos/síntese química , Piperidonas/síntese química , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Acetatos/farmacocinética , Acetatos/farmacologia , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Hepatócitos/metabolismo , Humanos , Macaca fascicularis , Camundongos , Camundongos Nus , Modelos Moleculares , Conformação Molecular , Transplante de Neoplasias , Piperidonas/farmacocinética , Piperidonas/farmacologia , Ligação Proteica , Ratos , Estereoisomerismo , Relação Estrutura-Atividade , Transplante Heterólogo , Proteínas rho de Ligação ao GTP/biossínteseRESUMO
An ab initio study of six carbon-to-carbon identity proton transfers is reported. They refer to the benzenium ion/benzene (C6H7(+)/C6H6), the 2,4-cyclopentadiene/cyclopentadienyl anion (C5H6/C5H5(-)), and the cyclobutenyl cation/cyclobutadiene (C4H5(+)/C4H4) systems and their respective noncyclic reference systems, that is, [structure: see text], [structure: see text] and [structure: see text]. For the aromatic C6H7(+)/C6H6 and C5H6/C5H5(-) systems, geometric parameters and aromaticity indices indicate that the transition states are highly aromatic. The proton-transfer barriers in these systems are quite low, which is consistent with a disproportionately high degree of transition-state aromaticity. For the antiaromatic C4H5(+)/C4H4 system, the geometric parameters and aromaticity indices indicate a rather small degree of antiaromaticity of the transition state. However, the proton-transfer barrier is higher than expected for a transition state with a low antiaromaticity. This implies that another factor contributes to the barrier; it is suggested that this factor is angle and torsional strain in the transition state. The question whether charge delocalization at the transition state might correlate with the development of aromaticity was also examined. No such correlation was found, that is, charge delocalization lags behind proton transfer as is commonly observed in nonaromatic systems involving pi-acceptor groups.
RESUMO
A kinetic study of the reversible deprotonation of the rhenium carbene complexes 1H(+)(O), 1H(+)(S) and 2H(+)(O) by carboxylate ions, primary aliphatic and secondary alicyclic amines, water and OH(-) in 50% MeCN-50% water (v/v) at 25 degrees C is reported. These carbene complexes are of special interest because in their deprotonated form they represent derivatives of the aromatic heterocycles furan, thiophene and benzofuran. Intrinsic rate constants (k(o) for Delta G degrees = 0) determined from appropriate Brønsted plots for these rhenium carbene complexes and for the corresponding selenophene (1H(+)(Se)) and benzothiophene (2H(+)(S)) derivatives investigated earlier follow the orders furan < selenophene < thiophene and benzofuran less, similar benzothiophene. These orders indicate that an increase in aromaticity leads to an increase in the intrinsic rate constant or a decrease in the intrinsic barrier. This is an unexpected result; it implies that, in contrast to common resonance effects, the development of aromaticity at the transition state is ahead of proton transfer, i.e., the percentage development of the aromatic stabilization energy at the transition state is higher than the percentage of proton transfer.