Preparation of an [18F]liposome using a novel "Click Chemistry" approach

Wednesday, October 26, 2011 — Poster Session III
10:00 a.m. – Noon	Natcher Conference Center	NHLBI	IMAG-37

Authors

• B Xu
• F Bhattacharyya
• C Li
• K Lane
• A Sulima
• G Griffiths

Abstract

Several methods for radiolabeling liposomes with various radionuclides have been developed since the discovery of liposomes four decades ago. PET imaging provides an effective method of noninvasively tracking and quantifying the distribution of liposomes in the body and is an excellent tool for developing liposome-based drugs and therapeutic radionuclides. Several liposome formulations in the size range of 90–100 nm are already clinically approved for drug delivery. The most useful radionuclide for PET imaging is 18F, but efficient 18F radiolabeling of a preformed liposome has not heretofore been described. Herein, we report the synthesis of an 18F-labeled liposome prepared by "Click Chemistry" using a [18F]23-azido-1-fluoro-3, 6, 9, 12, 15, 18, 21-heptaoxatricosane hapten and an dibenzylcyclooctyne (DBCO)-appended liposome. The DBCO-liposome was first prepared within a limited size range of 80-90nm. The [18F]azide ligand was synthesized in 24% uncorrected radiochemical yield in 50 minutes. The [18F]azide ligand and the DBCO-liposome were combined at 37°C. The uncorrected radiochemical yield was up to 63% in a 50min synthesis time. The overall uncorrected radiochemical yield was 15% in a 90min synthesis time starting from [18F]fluoride. The result represents a viable method for radiolabeling a preformed liposome with 18F.

back to top