RESUMO
Biocompatible poly(iohexol) nanoparticles, prepared through cross-linking of iohexol and hexamethylene diisocyanate followed by coprecipitation of the resulting cross-linked polymer with mPEG-polylactide, were utilized as contrast agents for in vivo X-ray computed tomography (CT) imaging. Compared to conventional small-molecule contrast agents, poly(iohexol) nanoparticles exhibited substantially protracted retention within the tumor bed and a 36-fold increase in CT contrast 4 h post injection, which makes it possible to acquire CT images with improved diagnosis accuracy over a broad time frame without multiple administrations.
Assuntos
Meios de Contraste/síntese química , Iohexol/síntese química , Nanopartículas/química , Polímeros/síntese química , Tomografia Computadorizada por Raios X , Animais , Meios de Contraste/administração & dosagem , Humanos , Iohexol/administração & dosagem , Células MCF-7/citologia , Camundongos , Camundongos Endogâmicos C57BL , Nanopartículas/administração & dosagem , Polímeros/administração & dosagem , Fatores de TempoRESUMO
The liposomes were prepared by reverse-phase evaporation technique. The morphology of the liposomes, the entrapment efficiency and the particle size distribution were evaluated. The CT signals of Iohexol liposomes in rabbits were compared with those of Iohexol injection in rabbits. The entrapment efficiency of Iohexol liposomes was 82.35% +/- 1.82%. The liposmes were spherical or ellipsoidal shape in shape. The mean diameter of the Iohexol liposomes was 207 7 nm. The polydispersity index was 0.355. The Zeta potential was--1.83 mV. The drug was highly entrapped into the liposomes with good reproduction and stability. The in vitro release of Iohexol liposomes was significantly slower than that of Iohexol,and was 98.57% at 24 h. Iohexol liposomes may reduce the dosage, prolong the effective time of the developing agent, and could reduce the side effects of Iohexol on the blood vessels and cerebral nerves.
Assuntos
Meios de Contraste/síntese química , Sistemas de Liberação de Medicamentos , Iohexol/síntese química , Lipossomos/síntese química , Animais , Meios de Contraste/química , Portadores de Fármacos , Iohexol/química , Lipossomos/administração & dosagem , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Coelhos , Distribuição AleatóriaAssuntos
Meios de Contraste , Radiologia/métodos , Ácidos Tri-Iodobenzoicos , Meios de Contraste/administração & dosagem , Meios de Contraste/síntese química , Humanos , Injeções Intravenosas , Cooperação Internacional , Iohexol/administração & dosagem , Iohexol/síntese química , Ácidos Tri-Iodobenzoicos/administração & dosagem , Ácidos Tri-Iodobenzoicos/síntese químicaRESUMO
RATIONALE AND OBJECTIVES: To prepare and characterize a new particulate contrast medium, cyclic carbonate of ioxilan (IX-C) particles, as a macrophage imaging agent for computed tomography (CT) enhancement of the liver. METHODS: Cyclic carbonate of ioxilan was synthesized from ioxilan, a nonionic water-soluble contrast agent. The IX-C particles prepared by a solvent extraction-evaporation method were characterized by size distribution, degradability, suspension stability, and median lethal dose. Pharmacokinetics of IX-C particles and their effectiveness in enhancing liver attenuation and in detecting hepatic tumors were evaluated using normal and VX2-tumor-bearing rabbits. RESULTS: The IX-C particles were biodegradable, with ioxilan and carbon dioxide as the degradation products. The particles had an average size of 1 to 2 microns and were stable in saline suspension. The median lethal dose determined for IX-C particles was 2.6 and 3.1 g/kg body weight for female and male rabbits, respectively. A dose of 200 mg iodine/kg body weight caused an increase of 38 Hounsfield units in liver attenuation. In rabbit, hepatic clearance of the contrast medium occurred in 2 days. A tumor barely visible in precontrast scans could be detected after contrast injection. CONCLUSIONS: Development of particulate contrast medium from nonionic contrast agents represents a new approach. Ioxilan carbonate particles have suitable physicochemical properties that warrant further studies before clinical evaluation.