RESUMEN
A series of (-)-beta-D-(2R,4R)-dioxolane-thymine-5'-O-aliphatic acid esters as well as amino acid esters were synthesized as prodrugs of (-)-beta-D-(2R,4R)-dioxolane-thymine (DOT). The compounds were evaluated for anti-HIV activity against HIV-1(LAI) in human peripheral blood mononuclear (PBM) cells as well as for their cytotoxicity in PBM, CEM and Vero cells. Improved anti-HIV potency in vitro was observed for the compound 2-4 (5'-O-aliphatic acid esters) without increase in cytotoxicity in comparison to the parent drug. Chemical and enzymatic hydrolysis of the prodrugs was also studied, in which the prodrugs exhibited good chemical stability with the half-lives from 3 h to 54 h at pH 2.0 and 7.4 phosphate buffer. However, the prodrugs were relatively labile to porcine esterase with the half-lives from 12.3 to 48.0 min.
Asunto(s)
Fármacos Anti-VIH/química , Fármacos Anti-VIH/farmacología , Dioxolanos/farmacología , Profármacos/química , Profármacos/farmacología , Timina/análogos & derivados , Animales , Fármacos Anti-VIH/toxicidad , Línea Celular , Chlorocebus aethiops , Dioxolanos/química , Dioxolanos/toxicidad , Estabilidad de Medicamentos , Semivida , Humanos , Leucocitos Mononucleares/efectos de los fármacos , Profármacos/toxicidad , Estereoisomerismo , Timina/química , Timina/farmacología , Timina/toxicidad , Células VeroRESUMEN
A series of phosphoramidate and phosphate prodrugs of DOT were synthesized via dichlorophosphate or H-phosphonate chemistry and evaluated for their anti-HIV activity against LAI M184V mutants in PBM cells as well as for their cytotoxicity. The antiviral and cytotoxic profiles of the prodrugs were compared with that of the parent compound (DOT), and it was found that four aryl phosphoramidates 5, 18, 20, and 26 showed a significant enhancement (8- to 12-fold) in anti-HIV activity without cytotoxicity. Chemical stability of these prodrugs was evaluated in phosphate buffer at pH values of biological relevance (i.e., pH 2.0 and 7.4). Enzymatic hydrolysis was also studied in esterase or lipase in buffer solution. Chemical stability studies indicate that the phosphoramidates have good chemical stability at pH 2.0 and at pH 7.4 phosphate buffer. Phosphoramidate prodrugs were hydrolyzed in vitro by esterase or lipase and found to be better substrates for lipases than for esterases. 1,3-Diol cyclic phosphates showed potent anti-HIV activity without increasing the cytotoxicity compared with that of DOT and have good chemical and enzymatic stability. Long-chain lipid phosphates, although showed potent anti-HIV activity, exhibited increased cytotoxicity.
Asunto(s)
Amidas/química , Fármacos Anti-VIH , Dioxolanos , VIH/efectos de los fármacos , Fosfatos/química , Ácidos Fosfóricos/química , Profármacos , Timina/análogos & derivados , Animales , Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/química , Fármacos Anti-VIH/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Chlorocebus aethiops , Dioxolanos/síntesis química , Dioxolanos/química , Dioxolanos/farmacología , Estabilidad de Medicamentos , Humanos , Hidrólisis , Cinética , Leucocitos Mononucleares/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Profármacos/síntesis química , Profármacos/química , Profármacos/farmacología , Estereoisomerismo , Relación Estructura-Actividad , Timina/síntesis química , Timina/química , Timina/farmacología , Células Vero/efectos de los fármacosRESUMEN
The synthesis, characterization, anti-HIV activity and cytotoxicity of dendrimers of (-)-beta-D-(2R, 4R)-dioxolane-thymine (DOT) and polyethylene glycol (PEG)-DOT conjugates are described. Dendrimers in this study were polyamidoamine (PAMAM) generation 2.0, 3.0, 5.0 and 6.0, along with 8.0-branched PEG with a molecular weight of 40 kDa. DOT was attached to PAMAM dendrimers or branched PEG via ester or phosphafte groups. Size exclusion chromatography was used to purify the dendrimers and PEG conjugates, which were characterized by NMR and MALDI-TOF mass spectrometry. The synthesized PAMAM dendrimers and PEG conjugates were evaluated for anti-HIV activity against HIV-1LAI in primary human peripheral blood mononuclear cells (PBMCs) and cytotoxicity in PBMCs, CEM and Vero cells. PAMAM dendrimers of DOT with ester linkages and particularly phosphate linkers showed an increase in anti-HIV potency in comparison with DOT alone (140- and 56-fold, respectively). Unfortunately, the PAMAM dendrimers also exhibited increased cytotoxicity. Anti-HIV activity of PEG-DOT conjugates was found to be lower than that of DOT.