RESUMEN
A proof of concept study has been conducted for the design of a porous biodegradable material containing nanocapsules and two actives with independent release-bimodal drug-eluting implants. Completely safe synthetic material free from risk of prion and virus contamination was tested in vivo, and a method for controlling the rate of biodegradation of poly-2-cyanoacrylic polymer was developed. Novel perfluorinated 2-cyanoacrylic esters have been applied for the chemical modification of polyethyl-2-cyanoacrlylate copolymers. Internal imide-cycle formation has been used to retard the rate of enzymatic hydrolysis of the 2-cyanoacrylic copolymer main chain.
RESUMEN
Tyrosine derivatives labeled with a short-living fluorine 18 isotope (T(1/2) 110 min), namely 2-[(18)F]fluoro-L-tyrosine (FTYR) and O-(2'-[(18)F]fluoroethyl)-L-tyrosine (FET), promising radiopharmaceutical products (RPP) for positron emission tomography (PET), were obtained by asymmetric synthesis. Accumulation of FTYR and FET in the rat tumor "35 rat glioma" and in abscesses induced in Vistar mouse muscles was studied and compared with that of a well-known glycolysis radiotracer 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG). It was shown that the relative accumulation indices of amino acid RPP were considerably lower than those of FDG. At the same time, tumor/muscle ratios were high enough (2.9 for FET and 3.9 for FTYR 120 min after injection) for reliable tumor visualization. The data obtained indicated a possibility in principle to use FTYR and FET for differentiated PET diagnostics of brain tumors and inflammation lesions. Of the tyrosine derivatives studied, FET seems to be the most promising agent due to a simple and easily automated method of preparation based on direct nucleophilic substitution of the leaving tosyloxy group of an enantiomerically pure Ni-(S)-BPB-(S)-Tyr(CH2CH2OTs) precursor by an activated [(18)F]fluoride.
Asunto(s)
Absceso/diagnóstico por imagen , Neoplasias Encefálicas/diagnóstico por imagen , Glioma/diagnóstico por imagen , Radiofármacos/síntesis química , Tirosina/análogos & derivados , Absceso/metabolismo , Animales , Neoplasias Encefálicas/metabolismo , Radioisótopos de Flúor , Fluorodesoxiglucosa F18/farmacocinética , Glioma/metabolismo , Marcaje Isotópico , Músculo Esquelético/diagnóstico por imagen , Músculo Esquelético/metabolismo , Trasplante de Neoplasias , Cintigrafía , Radiofármacos/farmacocinética , Ratas , Ratas Wistar , Distribución Tisular , Trasplante Heterólogo , Tirosina/síntesis química , Tirosina/farmacocinéticaRESUMEN
The enantiomeric and diastereoisomeric analysis of nonproteinogenic methyl and hydroxy amino acids, obtained by asymmetric synthesis with the aid of a chiral regenerable reagent, has been carried out by liquid chromatography.