[en] This work reports the synthesis, radiolabeling and preliminary biodistribution results in tumor-bearing mice of [^99mTc(CO)₃(IDA-PEG₃-CB)]^-. The novel chlorambucil derivative was successfully synthesized by conjugation of iminodiacetic acid (IDA) to chlorambucil via a pegylated linker. The ligand could be labeled by [^99mTc(CO)₃]⁺ core in high yield to get [^99mTc(CO)₃(IDA-PEG₃-CB)]^-, which was very hydrophilic and was stable at room temperature. Biodistribution studies in tumor-bearing mice showed that [^99mTc(CO)₃(IDA-PEG₃-CB)]^- accumulated in the tumor with favorable uptake and retention. The good accumulation in tumor tissue with high tumor/muscle ratios warrants further research to improve tumor targeting efficacy and pharmacokinetic profile of radiolabeled chlorambucil derivative by structural modification. (author)

[en] This study reports the synthesis, radiolabeling and preliminary biodistribution results of [^99mTc(CO)₃(MN-TZ-BPA)]⁺ in tumor-bearing mice. The novel nitroimidazole derivative was successfully synthesized by conjugation of bis(pyridin-2-ylmethyl)amine (BPA) to 2-methyl-5-niroimidazole via 'click' reaction. The ligand could be labeled by [^99mTc(CO)₃]⁺ core in high yield to get [^99mTc(CO)₃(MN-TZ-BPA)]⁺, which was very hydrophilic and was stable at room temperature. Biodistribution studies in tumor-bearing mice showed that [^99mTc(CO)₃(MN-TZ-BPA)]⁺ accumulated in the tumor with certain initial uptake while poor retention. The rapid clearance from normal organs with favorable tumor/muscle ratios warrants further research to improve tumor targeting efficacy and pharmacokinetic profile of radiolabeled nitroimidazoles by structural modification. (author)

[en] This work reports the synthesis and preliminary biodistribution results of [¹³¹I]SIB-PEG₄-CHC in tumor-bearing mice. The tributylstannyl precursor ATE-PEG₄-CHC was synthesized by conjugation of ATE to amino pegylated colchicine NH₂-PEG₄-CHC. [¹³¹I]SIB-PEG₄-CHC was radiosynthesized by electrophilic destannylation of the precursor with a yield of ∼44%. The radiochemical purity (RCP) appeared to be >95% by a Sep-Pak cartridge purification. [¹³¹I]SIB-PEG₄-CHC was lipophilic and was stable at room temperature. Biodistribution studies in tumor-bearing mice showed that [¹³¹I]SIB-PEG₄-CHC cleared from background rapidly, and didn't deiodinate in vivo. However, the poor tumor localization excluded it from further investigations as a tumor-targeted radiopharmaceuticals. (author)

[en] This work reports the synthesis, radiolabeling and preliminary biodistribution results in tumor-bearing mice of the ^99mTc(CO)₃-AOPA colchicine conjugate. The novel ligand was successfully synthesized by conjugation of N-(acetyloxy)-2-picolylamino (AOPA) to deacetylcolchicine via a short carbonyl-methylene linker. Radiolabeling was performed in high yield with [^99mTc(CO)₃]⁺ core. ^99mTc(CO)₃-AOPA colchicine conjugate was hydrophilic and was stable at room temperature. Biodistribution studies in tumor-bearing mice showed that ^99mTc(CO)₃-AOPA colchicine conjugate accumulated in the tumor with good uptake and retention. However, its clearance from normal organs was not so fast, resulting in poor T/NT ratios. Further modification on the linker or/and ^99mTc-chelate to improve the tumor targeting efficacy and in vivo kinetic profiles is currently in progress. (author)

[en] This work reports the synthesis, radiolabeling and preliminary biodistribution results in tumor-bearing mice of [^99mTc(CO)₃(PA-TZ-CHC)]⁺. The novel colchicine (CHC) ligand was successfully synthesized via 'click' reaction. Radiolabeling was performed in high yield with [^99mTc(CO)₃]⁺ core to get [^99mTc(CO)₃(PA-TZ-CHC)]⁺, which was hydrophilic and cationic, and was stable at room temperature. Biodistribution studies in tumor-bearing mice showed that [^99mTc(CO)₃(PA-TZ-CHC)]⁺ accumulated in the tumor with good uptake while comparatively low retention. The clearance of the ^99mTc-complex from normal organs was fast, resulting in increasing tumor/blood and tumor/muscle ratios. The promising results in preliminary biodistribution studies warrant further research to improve tumor targeting efficacy and pharmacokinetic profile of radiolabeled CHC derivative by structural modification.(author)

[en] To develop novel ^99mTc labeled nitroimidazole imaging agents for imaging tumor hypoxia, ^99mTc labeled ethylene diamine tetraacetic acid derivative of 4-nitroimidazole was reported by us earlier, which showed disadvantage of an unsatisfactory tumor-to-blood ratio. Therefore, 2-nitroimidazole was adopted as a pharmacophore to synthesize EDTA-2-EtNHNM, which was radiolabeled with ^99mTc in high yield to achieve ^99mTc-EDTA-2-EtNHNM. ^99mTc-EDTA-2-EtNHNM was hydrophilic and exhibited good in vitro stability. Cellular experiment demonstrated its hypoxic selectivity while biodistribution results showed improved tumor-to-blood and tumor-to-muscle ratios. SPECT imaging studies of ^99mTc-EDTA-2-EtNHNM indicated obvious accumulation in tumor, suggesting its potential to be a radiotracer for imaging tumor hypoxia. (author)