Biolocalization and cell labeling properties of neutral-lipophilic 99mTc-amine-phenol chelates

^99mTc-diamine-diphenol chelates are neutral lipophilic chelates exhibiting good stability in aqueous solutions. The cell labeling and biolocalization properties of four different ^99mTc-amine-phenol complexes were determined. All four chelates readily labeled leukocytes and RCBs in high yields. Even though ^99mTc was retained by the cells, the elution rate of ^99mTc from the labeled cells in plasma at 37 °C was unacceptably high for potential utility in scintigraphic imaging. The uptake of ^99mTc in brain or heart following i.v. injection of the chelates in rats was low and clearance of activity from the blood was slow.