RT Journal Article
SR Electronic
T1 In vitro and in vivo properties of radiolabeled DSPE-DTPA liposomes
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 1689
OP 1689
VO 56
IS supplement 3
A1 Tessa van der Geest
A1 Peter Laverman
A1 Josbert Metselaar
A1 Otto Boerman
YR 2015
UL http://jnm.snmjournals.org/content/56/supplement_3/1689.abstract
AB 1689 Objectives Liposomes are used as a drug carrier system to improve therapeutic efficacy of water soluble drugs. To track these liposomes in vivo, liposomes can be radiolabeled with 111In-oxine. Generally, DTPA is incorporated in the liposomes, however it is unknown whether incorporation of DTPA improves the stability of liposomes labeled with 111In-oxine. Alternatively, liposomes can be labeled with 111InCl3 by incorporating DTPA-conjugated DSPE in the lipid bilayer. Here we compared the in vitro properties of DSPE-DTPA liposomes with those of DTPA- and empty liposomes.Methods DSPE-DTPA-, DTPA- and empty liposomes were prepared by injection of an ethanolic lipid solution into an aqueous dispersion medium, followed by extrusion and size measurements using dynamic light scattering. DTPA- (88 nm in diameter) and empty (84 nm) liposomes were labeled with 111In-oxine, and DTPA-DSPE-PEG liposomes (83 nm) were labeled with 111InCl3. Labeling efficiency at increasing specific activity and stability in human serum at 37°C was determined. The in vivo properties of 111In-labeled liposomes were determined in an experimental arthritis model.Results Radiolabeling yields for DSPE-DTPA liposomes were high (>90%) up to specific activity of 15 GBq/mmol total lipid. Radiolabeling yields for DTPA liposomes were also high (>90%), but only when specific activity did not exceed 150 MBq/mmol total lipid. Both preparations were stable in human serum for at least 48 h at 37°C (>98%). Radiolabeling yields for empty liposomes were lower (>60%) at a specific activity of 150 MBq/mmol total lipid and after 48 h at 37°C only 68% of the 111In-activity remained associated with the liposomes. In mice with collagen-induced arthritis the 111In-labeled DSPE-DTPA liposomes accumulated in the inflamed joints (up to 40 %ID/g in severely inflamed joints).Conclusions In vitro properties of DTPA-DSPE liposomes are superior to those of DTPA- and empty liposomes. In addition, 111In-labeled DSPE-DTPA liposomes showed excellent in vivo properties.Research Support NanoNextNL 03D.06