title: Diffusion of polymer gel implants.
abstract: Crosslinked polyacrylamide and polyvinylpyrrolidone gels have been used to subcutaneously implant (125)I-labeled immunoglobulin, (125)I-labeled luteinizing hormone, (125)I-labeled bovine serum albumin, (125)I-labeled insulin, [(3)H]prostaglandin F(2alpha), and Na(125)I into hamsters. From the rates of absorption of the solutes, their diffusion coefficients were determined. The diffusion coefficients showed a logarithmic dependence on implant polymer concentration and solute molecular weight. Release of the solutes from gel preparations incubated 10 mM phosphate buffer (pH 7.2) at 37 degrees revealed a similar relationship between solute diffusion coefficient, molecular weight, and the concentration of polymer. A general equation was derived that gives the expected diffusion coefficient of a substance in a polymer gel from its molecular weight, diffusion coefficient in solvent, and polymer concentration of the gel.
mesh_terms: D000178:Acrylamides; D000818:Animals; D001682:Biological Availability; D006224:Cricetinae; D003692:Delayed-Action Preparations; D004058:Diffusion; D005782:Gels; D006863:Hydrogen-Ion Concentration; D007136:Immunoglobulins / Q000008:administration & dosage; D007328:Insulin / Q000008:administration & dosage / Q000378:metabolism; D007457:Iodine Radioisotopes; D007986:Luteinizing Hormone / Q000008:administration & dosage; D008647:Mesocricetus; D010592:Pharmaceutic Aids; D011205:Povidone; D011453:Prostaglandins / Q000008:administration & dosage / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000008:administration & dosage / Q000378:metabolism; D013696:Temperature; D014316:Tritium
chemical_list: D000178:Acrylamides; D003692:Delayed-Action Preparations; D005782:Gels; D007136:Immunoglobulins; D007328:Insulin; D007457:Iodine Radioisotopes; D010592:Pharmaceutic Aids; D011453:Prostaglandins; D014316:Tritium; D012710:Serum Albumin, Bovine; D007986:Luteinizing Hormone; D011205:Povidone