Anisotropy of indium-111 in cetyltrimethylammonium bromide solutions

The perturbed angular correlation (PAC) technique, which employs the cascading decay of the radionuclide indium-111 (111In), has been used to observe anisotropic changes in various pharmaceutical systems. Changes in the tumbling rate (anisotropy) of the 111In nucleus were indicative of changes in the local physical environment of the radionuclide following dissolution or drug release from labelled dosage forms. The present communication reports preliminary data on the effect of a cationic surfactant on the anisotropy of 111In solutions. (Auth.)