[Kinetics of the in vitro dissolution of cadmium oxide particles in human plasma and cadmium binding to plasma proteins--effect of chelating agents].

The solubility in biological liquids of particles which penetrate as far as alveolar compartment, has a determinant influence on their absorption into the blood stream. The experiments conducted in vitro have enabled cadmium oxide dissolution parameters in human plasma at 37 degrees C to be calculated, as well as cadmium dissolved concentration according to time and cadmium particle level, initial dissolution rate and dissolved cadmium concentration at saturation. The smaller the particles, the quicker they dissolve. Dissolved cadmium is distributed between diffusible cadmium (2%) and cadmium binding proteins (98%) chiefly in albumin and IgA. The cadmium binding protein fraction can be mobilized by chelating agents. In vitro studies allow the determination of mobilized cadmium fraction according to time. The calco sodic salt of ethylen diaminotetraacetic acid and N-acetyl-DL penicillamine are the most energetic compounds, compared to meso 2,3 dimercaptosuccinic acid, and 2,3 dimercapto-1-propan sulfonic acid.