In vitro and in vivo characterization of a 99mTc complex with tris(hydroxymethyl)phosphine (THP).

The water-soluble, monophosphine ligand tris(hydroxymethyl)phosphine (THMP) was complexed with 99mTc. The 99mTc-THMP was formed in high radiochemical purity by simply mixing 99mTcO4- with THMP over a wide pH range. In vitro and in vivo studies indicated the complex to be highly stable under the respective conditions. HPLC analysis indicated a singular species with a retention time identical to the known [ReO2(THMP)4]1 complex. Results show that the hydroxymethylphosphine functionality is attractive for use in designing new 99mTc radiopharmaceuticals.