Radiolabeled, folate-conjugated liposomes as tumor imaging agents: Formulation and in vitro evaluation

The Formulation of Methylene Blue Encapsulated, Tc-99m Labeled Multifunctional Liposomes for Sentinel Lymph Node Imaging and Therapy

“…These results are in agreement with the previous studies. [28][29][30] In vitro release of MB encapsulated, nanosized Lipoid S PC:PEG2000-PE:Chol:DTPA-PE and DPPC:PEG2000-PE:Chol:DTPA-PE liposomes were evaluated by dialysis method. 27 Lipoid S PC containing liposomes designated slightly faster release of MB when compared with DPPC containing ones (p ˃ 0.05).…”

“…DTPA is one of the most commonly used metal chelator agent nowadays for efficiently radiolabel liposomes for imaging. 26,28,29 Chelating agent DTPA conjugates to the amino head group with -COOH group and by this way while PE was incorporated with the lipid bilayer of liposomes, Tc-99m was incorporated with DTPA with a high efficiency. 25,26 Zeta potential exhibits the magnitude of the electrostatic repulsion/attraction between particles.…”

“…33 As a result, leakage of MB from Lipoid S PC liposomes was found to be higher than DPPC liposomes which is compatible with previous studies. [28][29][30] In vitro release profiles of liposomes are meaningful for predicting an efficient therapeutic effect. The release of MB is faster from liposomes composed of liquid-crystalline type phospholipids, depending on the distance within the polar head groups of liquid crystalline-type phospholipids, and is also faster than in gel state phospholipids.…”

“…SnCl2.2H2O (1 mg.mL -1 ) and 1.5 mCi of Tc-99m were incubated with liposomes for 30 minutes by shaking to allow transchelation. 28,29 After incubation, liposomes were dialyzed against HEPES (1 M, pH 7.4) buffer for 5 hours at 4°C to remove unchelated Tc-99m by cellulose ester dialysis membrane (3,500-Da cut-off size). After removal of free Tc-99m, the radioactivity of liposomes was measured by a gamma counter.…”

Targeted Alpha Therapy and Nanocarrier Approach

“…96,118 The combination of diagnostic or therapeutic radionuclides or contrast agents with liposomes for effective delivery and image-guided drug delivery is commonly searched for the diagnosis and/or therapy of different diseases especially cancer. 88,117,[119][120][121][122][123] For the therapy of tumors having low surface expression levels of molecular targets, 225 Ac and its a particle emitting daughters-encapsulated liposomes were prepared. 124,125 It was reported that passive 225 Ac-encapsulated liposomes can stably retain 225 Ac for 30 d. However, this resulted in low encapsulated activities.…”