[Preparation of liposome-mediated 99m-technetium-labeled antisense oligonucleotides of c-myc mRNA].

To explore the preparation method of liposome-mediated 99m-technetium-labeled antisense oligonucleotides of c-myc mRNA and lay foundations for antisense imaging and treatment, antisense oligonucleotides (DNA) with 15 bases and di-functional chelate, hydrazino nicotinamide derivatives, were synthesized. After DNA combined with chelate, they were labeled with 99m-technetium to form compounds, 99mTc-chelate-DNA (99mTc-DNA), and were purified through Sep-Pak reverse column(C18, Waters) by using methanol and water as eluent. The leaching curve was made; the labeling efficiency was calculated. The products were then encapsulated with cation liposome to form liposome-mediated 99mTc-DNA. The radiochemical purity and stability of the liposome-mediated 99mTc-DNA were tested through strip chromatography. The labeling efficiency was 63.37% +/- 3.51% at the radioactive concentration of 1480 MBq, 62.52% +/- 3.69% at that of 740 MBq, 59.82% +/- 5.12% at that of 592 MBq. There were no significant differences between these labeling efficiencies. The radiochemical purity was 96.47% +/- 3.01%. The liposome-mediated radiolabeled antisense oligonucleotides were stable after incubation with water or serum. Therefore liposome-mediated radiolabeled antisense oligonucleotides could be obtained through hydrazino nicotinamide derivatives as di-functional chelate and liposome as vector.