Use of Radiolabeled Liposomes for PEG-Liposome-Based Drug Targeting and Diagnostic Imaging Applications

PLA-PEG nanocapsules radiolabeled with 99mTechnetium-HMPAO: Release properties and physicochemical characterization by atomic force microscopy and photon correlation spectroscopy

“…6). Phillips (1998) has shown that liposomes are able to retain 99m Tc-HMPAO in plasma at 37 • C for as much as 90 h. However, comparative and quantitative analysis of the ability of the both nanosystems to entrap this radiotracer have not been performed and should be evaluated in further experiments. On the other hand, when the 99m Tc-HMPAO was only incubated with the already formed PLA-PEG NC, 70% of the radioactivity was released in the first 30 min and 90% in 120 min, suggesting that in this case 99m Tc-HMPAO was not truly encapsulated into the NC structure, being rapidly desorbed when in contact with the release media.…”

“…1, radiolabeling of d,l-HMPAO may give rise to two 99m Tc-labelled enantiomers with almost identical properties (Vanderghinste et al, 2003). The employment of the 99m Tc-HMPAO complex in the preparation of new types of radiopharmaceuticals such as the radiolabeled liposomes has been studied by several authors (Goins et al, 1993;Phillips, 1998;Laverman et al, 1999;Boerman et al, 2000). However, studies with liposomes have been limited because of inherent problems such as low encapsulation efficiency, poor storage stability (Soppimath et al, 2001) and a high incidence of side effects after i.v.…”