2.9. Efficiency and stability of the radiolabelling in serum

Samples of the radiolabelled liposomes or ¹¹¹In:EDTA were spotted in glass microfibre chromatography paper impregnated with silica gel. These strips were then developed using a mobile phase of 50 mM EDTA in 0.1 M ammonium acetate. Strips were placed on a multi-purpose storage phosphor screen (Cyclone ®, Packard, Japan) and kept in an autoradiography cassette (Kodak Biomax Cassette ®) for 10 min. Quantitative autoradiography counting was then carried out using a cyclone phosphor detector (Packard ®, Australia). The labelling stability was tested by incubation of the radio-conjugates in the presence or absence of foetal bovine serum (FBS). Samples were diluted in 50% FBS or PBS [1:2 (v/v)], and incubated for 24 h at 37 °C. The percentage of ¹¹¹In (immobile spot) still conjugated to the liposomes was evaluated by TLC, using the same protocol, as described above.