6-alkoxymethyl-3-hydroxy-4H-pyranones: potential ligands for cell-labelling with indium

We have identified ligands for cell labelling with indium-111: 3-hydroxy-6- propoxymethyl-4H-pyran-4-one and 6-butoxymethyl-3-hydroxy-4H-pyran-4one. Th e leucocyte labelling efficiencies of In-111 complexes of these ligands wer e higher and label stabilities were found to be similar compared with those obtained using In-111-tropolonate, High labelling efficiencies of neutroph ils and lymphocytes were achieved with In-111 complexes of pyranones. Tropo lone was found to have a greater inhibitory effect on metalloenzymes and to cause greater impairment of platelet function than 3-hydroxy-6-propoxymeth yl-4H-pyran-4-one. Thus 6-alkoxymethyl-3-hydroxy-4H-pyran-4-ones may have a dvantages over current ligands used in cell labelling with In-111.