A simple method for producing a technetium-99m-labeled liposome which is stable In Vivo

William T. Phillips, Alan S. Rudolph, Beth Goins, James H. Timmons, Robert Klipper, Ralph Blumhardt

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147 Scopus citations


A new method for labeling preformed liposomes with technetium-99m (99mTc) has been developed which is simple to perform and stable in vivo. Previous 99mTc-liposome labels have had variable labeling efficiencies and stability. This method consistently achieves high labeling efficiencies (> 90%) with excellent stability. A commercially available radiopharmaceutical kit-hexamethylpropyleneamine oxime (HM-PAO)-is reconstituted with 99mTcO-4 and then incubated with preformed liposomes that encapsulate glutathione. The incubation takes only 30 min at room temperature. Liposomes that co-encapsulate other proteins such as hemoglobin or albumin, in addition to glutathione, also label with high efficiency. Both in vitro and in vivo studies indicate good stability of this label. Rabbit images show significant spleen and liver uptake at 2 and 20 h after liposome infusion without visualization of thyroid, stomach or bladder activity. This labeling method can be used to study the biodistribution of a wide variety of liposome preparations that are being tested as novel drug delivery systems. This method of labeling liposomes with 99mTc may also have applications in diagnostic imaging.

Original languageEnglish (US)
Pages (from-to)539-543,545-547
JournalInternational Journal of Radiation Applications and Instrumentation.
Issue number5
StatePublished - Jul 1992

ASJC Scopus subject areas

  • Medicine(all)


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