BIOCHEMISTRY OF METALLOCENES .2. ORGAN DISTRIBUTION AND THYMUS AFFINITY OF CINNAMOYL-[RU-103]RUTHENOCENE

Abstract

Metallocenes, labeled with 103Ru, are potential radiopharmaceuticals for use in nuclear medicine diagnosis. Ruthenocene derivatives with oxopropene side-chains were administered to mice and rats to study their biochemical properties. Excretion rates and organ distributions of 103RuCl3 and Cinnamoyl-103Ru-ruthenocene were very different. While 103RuCl3 was relatively evenly distributed in the body, the metallocene deriative was concentrated in liver, lungs and spleen after i.v. injection. After i.p. injection a high thymus affinity was observed and autoradiography showed the site of 103Ru accumulation was in thymocytes. The thymus affinity was diminished by corticoid pretreatment and raised by inhibition of phagocytosis (BeSO4). The mechanism of accumulation in the thymus and a possible clinical application are discussed.