Synthesis of Tc-D,D-HMPAO and Tc-L,L-HMPAO and their comparison of chemical and biological properties

Tc- - and Tc- -HMPAO were synthesized. The stability of Tc- - and Tc- -HMPAO in vitro is similar to that of d,l-isomers by the spectrophotometric and three strips methods. Cerebral uptake (%D in brain) for the -isomer is higer than the - and d,l-isomer in rats. Delayed studies shows that Tc- -HMPAO reveals less washout and reflects a higher cerebral deposition properties than the - and d,l-isomer.