RADIOIODINATED METHYLENE-BLUE FOR MELANOMA TARGETING - CHEMICAL CHARACTERIZATION AND TUMOR SELECTIVITY OF LABELED COMPONENTS

Radioiodinated methylene blue contains a mixture of components showing selective uptake in human pigmented melanoma, and it has potential fo r imaging and therapy. Nuclear magnetic resonance and mass spectroscop ic studies show that the majority of the radioactivity (85%) is in the form of monoiodinated methylene blue, 4-iodo-3-methylamino-7-dimethyl aminophenaza thionium chloride. The amino group ortho to iodine has be come demethylated to a mono-methylamino group, The remainder (15%) of the mixture is the doubly labelled 4,5-diiodo-3,7-bis(methylamino) phe nazathionium chloride. The separated components show similar tumour se lectivity in athymic mice bearing human pigmented melanomas. (C) 1997 Elsevier Science Inc.