Studies on the Usefulness of Radioisotopes in Pharmaceutical Sciences

The use of radioisotopes and radiation is indispensable in the research of life science, especially in pharmaceutical sciences. Research topics in pharmaceutical sciences are mainly classified into three research fields as follows. (1) Trace elements in living systems and environment, where many kinds of tracers and neutron activation analysis are used. (2) Radioisotopes in the development of new pharmaceutics, where a wide variety of radioisotopes are needed for radioimmunoassay, radioreceptor assay, pharmacokinetics, imaging by autoradiography, radioprobes, drug delivery systems, and gene technology. (3) Radiopharmaceutics in nuclear medicine, where not only in vitro and in vivo diagnostic radiopharmaceutics but also in vivo therapeutic radiopharmaceutics have extensively been developed. Since 1971, we have used many tracers, and performed neutron activation analysis (NAA) method (Table 1) to know the chemical action mechanism of radioprotective agents, uptake of trace elements and glucose into the cells and organs, state of essential trace elements in organs of animals, and metal incorporations in subcellular particles and organs in experimental animals that were treated with metallo-pharmaceutics as well as metal complexes as candidates for future metallo-pharmaceutics. This review article describes progress in our investigation on the research of pharmaceutical sciences, focusing on the following three topics. (i) Mixed disulfide formation catalyzed by Cu(II) in relation to the radioprotective ability of a radioprotector, cysteamine (2-mercaptoethylamine). (ii) Suppression of reactive oxygen species (ROS) in the skin of live animals given oral administrations of Zn(II) and its complexes in relation to the skin damage under ultra-violet (UV) light. (iii) Improvement of diabetes mellitus by insulin-mimetic vanadyl(IV) (VO(II)) complexes.