ABSTRACT
The diffusion of latex particles and low molecular weight fluorescein analogues in homogenous, well-defined calcium alginate gel matrices was studied. The experimental results indicate that the different types of diffusion probes are retarded by different mechanisms in the gel. The positively charged low molecular weight substance experienced some degree of retardation by the gels, but the diffusion rate of the uncharged low molecular weight substance was little influenced by gel composition. A wide range of diffusion rates was observed for the particles in the various gel compositions.
Subject(s)
Alginates/chemistry , Algorithms , Chemical Phenomena , Chemistry, Physical , Coloring Agents , Data Interpretation, Statistical , Diffusion , Fluorescein , Gels/chemistry , Glucuronic Acid/chemistry , Hexuronic Acids/chemistry , Latex , Molecular WeightABSTRACT
Localised radiotherapy by instillation of radiolabeled particles is being used to treat rheumatoid arthritis and certain tumors. Such therapy is limited to organs and tissues capable of retaining the radioactive compound until the radioactivity is sufficiently low, and the leakage to other parts of the body is no longer unacceptable. In this study, radiolabeled particles, i.e. 90Y-silica colloid particles, were encapsulated in calcium alginate gels, and the leakage of radioactivity from the gels was monitored. The purpose of the study was to develop a formulation suitable for the localised delivery of radiation therapy to a wide range of organs and tissues. An injectable gel formulation was developed, liberating only small amounts of radioactivity into the surrounding medium. The formulation is a viscous liquid at room temperature and forms a gel on heating to normal body temperature. Thus, it should be suitable for the localised delivery of radiolabeled particles to a wide range of organs and tissues. The study also includes a formulation exhibiting time-dependent gelation. However, this formulation was not found to be suitable for the purpose.
Subject(s)
Radiopharmaceuticals/administration & dosage , Radiopharmaceuticals/chemistry , Radiotherapy , Alginates , Beta Particles , Chemistry, Pharmaceutical , Colorimetry , Gels , Glucuronic Acid , Hexuronic Acids , Hydrogen-Ion Concentration , Liposomes , Temperature , Viscosity , Yttrium Radioisotopes/chemistryABSTRACT
The diffusion of high molecular weight dextran samples and low molecular weight quinine sulphate in homogenous calcium alginate gel matrices was studied. An experimental design suitable for studying the diffusion of substances from or through a gel sample was established. The experimental results indicate that the different types of molecules diffuse in the gel by different mechanisms. The diffusion rate of the molecules in the gel is dependent on gel composition.
