科研之友
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摘要
The use of Tc-99m for developing cancer specific radiopharmaceuticals aims to translate effective products to clinical use. A class of radiopharmaceuticals, based on size accumulation is presently utilized for sentinel lymph node (SLN) detection: Tc-99m-sulfur colloid, filtered Tc-99m-sulfur colloid and microcolloids of Tc-99m-labelled albumin but none of these agents has ideal properties regarding the selective accumulation in sentinel node. Moreover, these compounds are uptaken also by distal lymph nodes. A lymphoscintigraphy agent requires high density of receptor substrate sites to achieve a specific receptor affinity required for a proper sentinel node detection. The solution could be given by mannose receptor-binding radiopharmaceuticals which can be synthesized with high specific activities compatible with typical target tissue receptor densities. %26lt;br%26gt;The radiolabelling of the mannosyl-cysteine-dextran macromolecules with Tc-99m (Dextran-S-Cysteine-Mannose) resulting in a high purity and stability radiolabelled conjugate, suitable for sentinel node detection with low distal (second) lymph node accumulation, as well as their in vivo biological evaluation are the aims of this study. Different radiolabelling strategies, including novel Tc-99m cores, were evaluated in order to select and optimize the most efficient and specific one. The quality control of radiolabelled conjugates using TLC and HPLC was performed; the radiochemical purities (RCPs) of the probes were in the range 93-99 %. The biological evaluation (ex-vivo biodistribution and specific uptake) was performed on Wistar rats sacrificed at 15, 30 and 60 min post injection (pi). The biological data show a rapid and highly specific sentinel node accumulation, up to 11 % ID, and a very good sentinel node extraction in respect of the second node in the chain up to 94 % at 1h pi.
- 出版日期2014
