RESUMEN
DGAT-1 is an enzyme that catalyzes the final step in triglyceride synthesis. mRNA knockout experiments in rodent models suggest that inhibitors of this enzyme could be of value in the treatment of obesity and type II diabetes. The carboxylic acid-based DGAT-1 inhibitor 1 was advanced to clinical trials for the treatment of type 2 diabetes, despite of the low passive permeability of 1. Because of questions relating to the potential attenuation of distribution and efficacy of a poorly permeable agent, efforts were initiated to identify compounds with improved permeability. Replacement of the acid moiety in 1 with an oxadiazole led to the discovery of 52, which possesses substantially improved passive permeability. The resulting pharmacodynamic profile of this neutral DGAT-1 inhibitor was found to be similar to 1 at comparable plasma exposures.
Asunto(s)
Diacilglicerol O-Acetiltransferasa/antagonistas & inhibidores , Inhibidores Enzimáticos/química , Oxazepinas/química , Administración Oral , Animales , Diacilglicerol O-Acetiltransferasa/metabolismo , Evaluación Preclínica de Medicamentos , Inhibidores Enzimáticos/farmacocinética , Inhibidores Enzimáticos/uso terapéutico , Semivida , Humanos , Ratones , Ratones Endogámicos C57BL , Ratones Obesos , Obesidad/tratamiento farmacológico , Oxadiazoles/química , Oxazepinas/farmacocinética , Oxazepinas/uso terapéutico , Unión Proteica , Ratas , Relación Estructura-ActividadRESUMEN
Alterations in fat metabolism, in particular elevated plasma concentrations of free fatty acids and triglycerides (TG), have been implicated in the pathogenesis of Type 2 diabetes, obesity, and cardiovascular disease. Acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1), a member of the large family of membrane-bound O-acyltransferases, catalyzes the final step in triacylglycerol formation. In the intestine, DGAT1 is one of the acyltransferases responsible for the reesterficiation of dietary TG. Following a single dose of a selective pharmacological inhibitor of DGAT1, PF-04620110, a dose-dependent inhibition of TG and vitamin A absorption postprandially was demonstrated in rodents and human subjects. In C57/BL6J mice, acute DGAT1 inhibition alters the temporal and spatial pattern of dietary lipid absorption. To understand the impact of DGAT1 inhibition on enterocyte lipid metabolism, lipomic profiling was performed in rat intestine and plasma as well as human plasma. DGAT1 inhibition causes an enrichment of polyunsaturated fatty acids within the TG class of lipids. This pharmacological intervention gives us insight as to the role of DGAT1 in human dietary lipid absorption.
Asunto(s)
Diacilglicerol O-Acetiltransferasa/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Absorción Intestinal/efectos de los fármacos , Oxazepinas/farmacología , Adolescente , Adulto , Animales , Estudios de Casos y Controles , Diacilglicerol O-Acetiltransferasa/genética , Diacilglicerol O-Acetiltransferasa/metabolismo , Grasas de la Dieta/sangre , Grasas de la Dieta/metabolismo , Relación Dosis-Respuesta a Droga , Enterocitos/metabolismo , Inhibidores Enzimáticos/farmacocinética , Ácidos Grasos Insaturados/sangre , Ácidos Grasos Insaturados/metabolismo , Femenino , Humanos , Mucosa Intestinal/metabolismo , Metabolismo de los Lípidos/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Persona de Mediana Edad , Oxazepinas/farmacocinética , Periodo Posprandial , Ratas , Ratas Sprague-Dawley , Triglicéridos/sangre , Triglicéridos/metabolismo , Vitamina A/metabolismoRESUMEN
A novel series of potent DGAT-1 inhibitors was developed originating from the lactam-based clinical candidate PF-04620110. Incorporation of a dioxino[2,3-d]pyrimidine-based core afforded good alignment of pharmacophore features and resulted in improved passive permeability. Development of an efficient, homochiral synthesis of these targets facilitated confirmation of predictions regarding the stereochemical-dependence of DGAT-1 inhibition for this series. Compound 10 was shown to be a potent inhibitor of human DGAT-1 (10 nM) and to suppress triglyceride synthesis at oral doses of <3mg/kg.
Asunto(s)
Diacilglicerol O-Acetiltransferasa/antagonistas & inhibidores , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Oxazepinas/química , Oxazepinas/farmacología , Pirimidinas/química , Pirimidinas/farmacología , Animales , Diacilglicerol O-Acetiltransferasa/metabolismo , Diseño de Fármacos , Inhibidores Enzimáticos/síntesis química , Humanos , Ratones , Modelos Moleculares , Oxazepinas/síntesis química , Pirimidinas/síntesis química , Triglicéridos/metabolismoRESUMEN
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: This study provides antimuscarinic agents for overactive bladder (OAB) display variable association with side effects mediated by the central nervous system (CNS), which may be of particular concern in the elderly. Adverse effects on CNS functioning are related to muscarinic receptor subtype selectivity and the ability of the agent to cross the blood-brain barrier, where P-gp plays a role in limiting permeability. WHAT THIS STUDY ADDS: This study provides a parallel investigation of CNS penetration of antimuscarinic OAB agents in vivo and assessment of physical properties and permeability in cell monolayers in vitro. It adds further understanding of the roles of passive transcellular permeability and P-gp in determining CNS penetration of antimuscarinic OAB agents. It also enables a comparison of CNS side-effect profiles of OAB agents with preclinical CNS penetration data. AIMS: To assess and compare the mechanisms of central nervous system (CNS) penetration of antimuscarinic overactive bladder (OAB) agents. METHODS: Physical properties were computed or compiled from the literature. Rats were administered 5-hydroxymethyl tolterodine (HMT), darifenacin, oxybutynin, solifenacin, tolterodine or trospium subcutaneously. At 1 h postdose, plasma, brain and cerebrospinal fluid (CSF) concentrations were determined using LC-MS/MS assays. Brain and plasma protein binding were determined in vitro. Permeability in the presence and absence of the efflux transporter P-glycoprotein (P-gp) was assessed in RRCK and MDCK-MDR1 transwell assays. RESULTS: Oxybutynin displayed extensive CNS penetration, with brain:plasma ratios (B:P), unbound brain:unbound plasma ratios (Kp,free) and CSF:free plasma ratios each >1. Tolterodine (B:P = 2.95, Kp,free = 0.23 and CSF:free plasma = 0.16) and solifenacin (B:P = 3.04, Kp,free = 0.28 and CSF:free plasma = 1.41) showed significant CNS penetration but with some restriction from CNS as indicated by Kp,free values significantly <1. 5-HMT, darifenacin and trospium displayed much lower B:P (0.03-0.16), Kp,free (0.01-0.04) and CSF:free plasma (0.004-0.06), consistent with poor CNS penetration. Permeability in RRCK cells was low for trospium (0.63 × 10(-6) cm s(-1) ), moderate for 5-HMT (11.7 × 10(-6) cm s(-1) ) and high for darifenacin, solifenacin, tolterodine and oxybutynin (21.5-38.2 × 10(-6) cm s(-1) ). In MDCK-MDR1 cells 5-HMT, darifenacin and trospium, were P-gp substrates, whereas oxybutynin, solifenacin and tolterodine were not P-gp substrates. CONCLUSIONS: Brain penetration was low for antimuscarinics that are P-gp substrates (5-HMT, darifenacin and trospium), and significant for those that are not P-gp substrates (oxybutynin, solifenacin and tolterodine). CNS adverse events reported in randomized controlled clinical trials show general alignment with the preclinical data described in this study.
Asunto(s)
Barrera Hematoencefálica/metabolismo , Encéfalo/metabolismo , Antagonistas Muscarínicos/farmacocinética , Vejiga Urinaria Hiperactiva/tratamiento farmacológico , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Animales , Compuestos de Bencidrilo/farmacocinética , Benzofuranos/farmacocinética , Línea Celular , Cromatografía Líquida de Alta Presión , Cresoles/farmacocinética , Humanos , Masculino , Ácidos Mandélicos/farmacocinética , Fenilpropanolamina/farmacocinética , Pirrolidinas/farmacocinética , Quinuclidinas/farmacocinética , Ensayos Clínicos Controlados Aleatorios como Asunto , Ratas , Ratas Sprague-Dawley , Receptores Muscarínicos/metabolismo , Succinato de Solifenacina , Espectrometría de Masas en Tándem , Tetrahidroisoquinolinas/farmacocinética , Tartrato de TolterodinaRESUMEN
Acyl-CoA:diacylglycerol acyltransferase-1 (DGAT-1) catalyzes the final committed step in the biosynthesis of triglycerides. DGAT-1 knockout mice have been shown to be resistant to diet-induced obesity and have increased insulin sensitivity. Thus, inhibition of DGAT-1 may represent an attractive target for the treatment of obesity or type II diabetes. Herein, we report the discovery and characterization of a potent and selective DGAT-1 inhibitor PF-04620110 (3). Compound 3 inhibits DGAT-1 with an IC50 of 19 nM and shows high selectivity versus a broad panel of off-target pharmacologic end points. In vivo DGAT-1 inhibition has been demonstrated through reduction of plasma triglyceride levels in rodents at doses of ≥0.1 mg/kg following a lipid challenge. On the basis of this pharmacologic and pharmacokinetic profile, compound 3 has been advanced to human clinical studies.