Development of a procedure for preparing 103Pd-microspheres of human blood albumin, a potential radiopharmaceutical for treatment of malignant tumors

Abstract

Sorption of Pd by albumin microspheres (AMSs) largely depends on the HCl concentration, reaching a maximum at an HCl concentration of 0.08 M. Sorption of Pd grows with an increase in its equilibrium concentration in 0.08 M HCl. The optimal amount of inactive palladium chloride as 103Pd carrier is 0.6 mg. Under these conditions, sorption of Pd by the protein matrix of albumin microspheres occurs with 70–80% efficiency. The reduction of the sorbed Pd in albumin microspheres leads to its considerable retention by the protein matrix of the microspheres. This was confirmed by biological studies on laboratory animals. The radionuclide clearance from the muscle tissue after local administration of 103Pd-AMSs with the reduced Pd is considerably slower compared to the unreduced Pd. The results obtained form a basis for the development of a novel radiopharmaceutical for intratissue radionuclide therapy of tumor diseases.