Study of plasma protein binding of two bifunctional chelates labelled with In-111

Summary: Distribution of many drugs in an organism is significantly influenced by their binding to plasma proteins. Determination of the extent of plasma binding for a concrete drug is necessary for prediction of its pharmacokinetics after administration to the organism. The aim of this thesis was to determine binding of a new bifunctional chelating agent DTPA-oxn labelled by 111 In to the plasma proteins of human and tree animal species and to compare these results with the plasma protein binding of routinely used radiopharmaceutical 111 In-DTPA. For measurement, a method of equilibrium dialysis at 37řC was used. The results show, that binding of 111 In-DTPA-oxn to the proteins of human, bovine, rabbit and rat plasma is similarly very low as at the compared chelate 111 In-DTPA and impossible to determine by equilibrium dialysis and pharmacokinetically unimportant. Radiochemical purity was also determined for both complexes by the method of thin layer chromatography ITLC-SG. Measured value was higher than 98% for each compound