Preparation and biological evaluation of 99mTc-timonacic acid as a new complex for hepatobiliary imaging

Abstract

Timonacic acid (TCA) was successfully labeled with ^99mTc. The influence exerted on the reaction by the substrate and reducing agent concentrations, pH of the reaction mixture, and reaction time was examined, and in vitro stability of ^99mTc-TCA was evaluated. The maximum labeling yield was 98.5 ± 0.6%. The complex was stable throughout the working period (6 h). A study of in-vivo biodistribution in mice showed that the maximum uptake of ^99mTc-TCA in the liver was 22.3 ± 0.3% of the injected activity per gram of the tissue or organ (% ID/g) at 30 min post injection. The clearance from the mice appeared to proceed via the circulation mainly through the kidneys and urine (approximately 56% of the injected dose at 1 h after injection). The liver uptake of ^99mTc-TCA is higher than that of ^99mTc-UDCA (ursodeoxycholic acid); therefore, ^99mTc-TCA shows more promise for liver SPECT.