Authors:Xiaobei Zheng, Feng Dong, Jing Yang, Xiaojiang Duan, Tingting Niu, Wangsuo Wu, and Jianjun Wang
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.
Authors:Junbo Zhang, Qian Yu, Jinfeng Huo, Yan Pang, Sheng Yang, Yining He, Tingting Tang, Chenchen Yang, and Xuebin Wang
The dimercaptosuccinic acid metronidazole ester (DMSAMe) was synthesized and radiolabeled with 99mTc to form the 99mTc-DMSAMe complex in high yield. The radiochemical purity of the 99mTc-DMSAMe complex was over 90%, as measured by TLC and by HPLC, without any notable decomposition at room temperature over
a period of 6 h. Its partition coefficient indicated that it was a lipophilic complex. The tumor cell experiment and the biodistribution
in mice bearing S 180 tumor showed that the 99mTc-DMSAMe complex had a certain hypoxic selectivity and accumulated in the tumor with high uptake and good retention. The
tumor/blood and tumor/muscle ratios increased with time, suggesting it would be a possible tumor hypoxia imaging agent.
Authors:N. Sadeghzadeh, M. Gandomkar, R. Najafi, M. Shafiei, S. Sadat Ebrahimi, A. Shafiee, and B. Larijani
A variety of human tumors like prostate and breast cancer express bombesin receptors. Due to this a new bombesin analogue
was labeled with 99mTc via HYNIC and tricine as a coligand and investigated further. Peptide was synthesized on a solid phase using Fmoc strategy.
Labeling with 99mTc was performed at 100 °C for 10 min and radiochemical analysis involved ITLC and HPLC methods. The stability of radiopeptide
was checked in the presence of human serum at 37 °C up to 24 h. Internalization was studied with the human GRP receptor cell
line PC-3. The biodistribution was studied in mice. Labeling yield of >98% was obtained corresponding to a specific activity
of ~80.9 GBq/μmol. Radiopeptide internalization into PC-3 cells was moderate and specific (10.7 ± 1.2% at 4 h). A high and
specific GRP receptor expressing mouse tumor and pancreas uptake (1.12 ± 0.08 and 1.04 ± 0.11% ID/g after 1 h respectively)
was also determined.
Authors:M. Motaleb, N. Al-Musayeib, W. Zaghary, and H. Shweeta
Shikonin was isolated from Ratanjot pigment then the obtained shikonin was well characterized. This study is aimed to optimize
radiolabeling yield of shikonin with 99mTc with respect to factors that affect the reaction conditions such as shikonin amount, SnCl2·2H2O amount, reaction time and pH of the reaction mixture. In vitro stability of the radiolabeled complex was checked and it
was found to be stable for up to 6 h. Biodistribution studies showed that, 99mTc–shikonin accumulate in tumor sites with higher T/NT than other currently available 99mTc(CO)3-VIP, 99mTc–nitroimidazole analogues and 99mTc–polyamine analogues indicating that shikonin deliver 99mTc to the tumor sites with a percentage sufficient for imaging and can overcome many drawbacks of other radiopharmaceuticals
used for tumor imaging.
Meropenem was successfully radiolabeled with 99mTc in high labeling yield (92 ± 2%) and stability (~6 h). 99mTc–meropenem showed high accumulation in tumor hypoxic tissue (4.193% injected dose/g organ). 99mTc–meropenem showed high ability to differentiate the tumor tissue from inflamed or infected tissues in different mice models
as its T/NT ratio ~4 in case of tumor mice model while T/NT ratio ~1 in case of inflamed mice model. So, 99mTc–meropenem showed high selectivity in comparison with FDG-PET and 99mTc-nitroimidazole analogues. Thus, 99mTc–meropenem could be used as a selective potential imaging agent for diagnosis of tumor hypoxia.