RESUMEN
The optimization of the pharmacokinetic performance of various 2-pyridone-containing human rhinovirus (HRV) 3C protease (3CP) inhibitors following oral administration to either beagle dogs or CM-monkeys is described. The molecules described in this work are composed of a 2-pyridone-containing peptidomimetic binding determinant and an alpha,beta-unsaturated ester Michael acceptor moiety which forms an irreversible covalent adduct with the active site cysteine residue of the 3C enzyme. Modification of the ester contained within these compounds is detailed along with alteration of the P(2) substituent present in the peptidomimetic portion of the inhibitors. The pharmacokinetics of several inhibitors in both dogs and monkeys are described (7 h plasma concentrations after oral administration) along with their human plasma stabilities, stabilities in incubations with human, dog, and monkey microsomes and hepatocytes, Caco-2 permeabilities, and aqueous solubilities. Compounds containing an alpha,beta-unsaturated ethyl ester fragment and either an ethyl or propargyl P(2) moiety displayed the most promising combination of 3C enzyme inhibition (k(obs)/[I] 170 000-223 000 M(-1) s(-1)), antiviral activity (EC(50) = 0.047-0.058 microM, mean vs seven HRV serotypes), and pharmacokinetics following oral administration (7 h dog plasma levels = 0.248-0.682 microM; 7 h CM-monkey plasma levels = 0.057-0.896 microM).
Asunto(s)
Antivirales/síntesis química , Antivirales/farmacología , Cisteína Endopeptidasas/metabolismo , Inhibidores de Proteasas/síntesis química , Inhibidores de Proteasas/farmacología , Piridonas/síntesis química , Piridonas/farmacología , Rhinovirus/enzimología , Proteínas Virales/metabolismo , Proteasas Virales 3C , Animales , Antivirales/farmacocinética , Disponibilidad Biológica , Proteínas Sanguíneas/metabolismo , Células CACO-2 , Perros , Diseño de Fármacos , Semivida , Hepatocitos/metabolismo , Humanos , Técnicas In Vitro , Indicadores y Reactivos , Macaca fascicularis , Espectroscopía de Resonancia Magnética , Masculino , Microsomas Hepáticos/metabolismo , Inhibidores de Proteasas/farmacocinética , Unión Proteica , Rhinovirus/efectos de los fármacos , Solubilidad , Relación Estructura-ActividadRESUMEN
Utilizing the tools of parallel synthesis and structure-based design, a new class of Michael acceptor-containing, irreversible inhibitors of human rhinovirus 3C protease (HRV 3CP) was discovered. These inhibitors are shown to inhibit HRV-14 3CP with rates of inactivation ranging from 886 to 31 400 M(-1) sec(-1). These inhibitors exhibit antiviral activity when tested against HRV-14 infected H1-HeLa cells, with EC(50) values ranging from 1.94 to 0.15 microM. No cytotoxicity was observed at the limits of the assay concentration. A crystal structure of one of the more potent inhibitors covalently bound to HRV-2 3CP is detailed. These compounds were also tested against HRV serotypes other than type 14 and were found to have highly variable activities.