In vitro precipitation behavior of trivalent lanthanides

Studies of the precipitation of trivalent lanthanides in vitro may be useful in understanding local retention in vivo. Chemical data, such as in vitro precipitation data, may be useful for predicting lung retention and clearance behaviour of aerosols. In vitro precipitation of 144Ce(III), 90Y(III), 169Yb(III) and 171Tm(III) at pH 7.3-7.4 and the effects of precipitants and ligands on the precipitation were studied. The effects of carrier and solvent pH on the in vitro precipitation of 144Ce(III) were also studied. These studies may provide a basis for assessing the observed differences in animal inhalation studies, and for improving the composition of stimulants of physiological solvents used for in vitro dissolution studies. (author)