Abstract
A folate-receptor-targeted 99mTc-radiopharmaceutical, [99mTc]Tc(CO)(3)DTPA-folate, was prepared by heating [99mTc]Tc(CO)(3)(H(2)O)(3)(+) in an aqueous solution of the previously reported DTPA-folate conjugate. The radiotracer was HPLC purified (> 98% radiochemical purity) and evaluated in vitro and in vivo as an agent for targeting folate-receptor-positive cells. [99mTc]Tc(CO)(3)DTPA-folate experienced high, folate-receptor-specific uptake in human KB tumor cells. Intravenous administration of [99mTc]Tc(CO)(3)DTPA-folate to athymic mice bearing KB cell tumor xenografts resulted in 99mTc tumor uptake of 1.8 +/- 0.5 and 3.3 +/- 0.2%ID/g (n = 3) at 30 minutes and 4 hours post-injection, respectively. Tumor uptake was reduced when folic acid was co-administered with the intravenous [99mTc]Tc(CO)(3)DTPA-folate, consistent with radiopharmaceutical localization being mediated by the folate receptor.
Publication types
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Evaluation Study
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Carrier Proteins / metabolism
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Folate Receptors, GPI-Anchored
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Folic Acid / analogs & derivatives
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Folic Acid / chemical synthesis*
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Folic Acid / pharmacokinetics*
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Folic Acid / pharmacology
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Humans
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KB Cells / diagnostic imaging
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KB Cells / metabolism*
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Mice
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Mice, Nude
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Neoplasm Transplantation
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Organotechnetium Compounds / chemical synthesis*
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Organotechnetium Compounds / pharmacokinetics*
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Radioligand Assay / methods*
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Radionuclide Imaging
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Radiopharmaceuticals / chemical synthesis
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Radiopharmaceuticals / pharmacokinetics
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Receptors, Cell Surface*
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Reproducibility of Results
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Sensitivity and Specificity
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Tissue Distribution
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Transplantation, Heterologous
Substances
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Carrier Proteins
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Folate Receptors, GPI-Anchored
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Organotechnetium Compounds
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Radiopharmaceuticals
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Receptors, Cell Surface
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technetium Tc 99m tricarbonyl DTPA-folate
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Folic Acid