Sterically stabilized liposomes as a carrier for α-emitting radium and actinium radionuclides

The alpha-particle emitting radionuclides Ra-223 (t(1/2) = 11.4 d), Ra-224 (t(1/2) = 3.6 d), and Ac-225(t(1/2) = 10.0 d) may have a broad application in targeted radiotherapy provided that they Could be linked to vehicles with tumor affinity. The potential usefulness of liposomes as carriers was studied in the present work. Radium and actinium radionuclides could he loaded in good yields into sterically stabilized lipsomes. Subsequent coating of the lipsomes with a folate-F(ab')(2) construct yielded a product with affinity towards tumor cells expressing folate receptors. Radionuclide loaded liposomes showed excellent stability in serum in vitro. (C) 2004 Elsevier Inc. All rights reserved.