TC-99M-LABELING AND BIODISTRIBUTION STUDIES OF SOME DIHYDRO-1,4-THIAZINE AND 1,3-THIAZOLIDINE-CARBOXYLIC ACID-DERIVATIVES

Cephalosporanic acids (CEPHAs) such as dihydro-1,4-thiazine derivative s and 2-hydroxyalkyl-1,3-thiazolidine-4-carboxyllc-acid (HOTCAs) are b oth important biologically active molecules and complexing agents for several metals such as Fe, Zn, Pb, etc. The simplest way for the study of the effect of complex formation upon the biochemistry of these com pounds requires radiolabeled complexes. As Te-99m radioisotope gives t he best opportunity for imaging the in vivo process, Tc-99m-CEPHAs and HOTCAs were prepared and investigated. It was found that biologically active molecules like CEPHAs and HOTCAs can be labeled with Te-99m wi th good radiochemical yields. In case of one CEPHA compound, low but d efinite myocardial uptake was observed, while 3 of the HOTCAs showed c haracteristic renal uptake and wash-out without visualization of any o ther organs than the urinary tract.