Pharmacokinetics of a new radiopharmaceutical based on alubmin microspheres and palladium-103 and modified by heat and radiation

The pharmacokinetics of albumin microspheres (AMS) labeled with 103 Pd ( 103 Pd-AMS) were studied in healthy mice after intramuscular injections. It was established that increasing the denaturation temperature of albumin from 136 to 200°C reduced the rate of 103 Pd elimination from muscle tissue. This effect can be explained by a decrease in the rate of 103 Pd-AMS proteolysis due to more extensive protein denaturation. Preliminary gamma irradiation ( 60 Co) of AMS prepared at 200°C produced a more significant deceleration of these processes. Increasing the irradiation dose from 0.1 to 1.0 MGy delayed AMS proteolysis and elimination of 103 Pd from the protein matrix as a result of an increasing degree of ASM cross-linking. The rate of 103 Pd elimination from muscle tissue was more rapid than that from tumor. This can be explained by faster AMS biodegradation in muscle tissue compared with tumor tissue.