Preparation, HPLC studies and biological behaviour of 99mTc- and 99mTcN-radiopharmaceuticals based on quinoline type ligands

^99mTc-Complexes of oxine (ox), thiooxine (tox) and 8-hydroxy-5-quinolinesulphonic acid (HQS) were prepared by ligand exchange of ^99mTcNCl₄⁻ and by stannous and dithionite reduction of ^99mTcO₄⁻. HPLC studies showed that the ^99mTcN-tox preparation was almost pure TcN(tox)₂. ^99mTc(Sn)-ox yielded a number of peaks upon HPLC with the major peak being identified as TcO(ox)₂Cl. No other Tc-complexes responsible for other chromatographic peaks were identified. Biodistribution studies in mice showed that all complexes except ^99mTc-HQS were cleared essentially by the hepatobiliary pathway. The ^99mTc-HQS preparations showed increased renal clearance due to the increased aqueous solubility of the complexes resulting from the presence of the sulphonate group on the quinoline ring.