| NUKLEONIKA 2011, 56(4):277-282
PREPARATION, QUALITY CONTROL AND BIODISTRIBUTION STUDIES
OF 165Dy-CHITOSAN FOR RADIOSYNOVECTOMY
Simindokht Shirvani-Arani1, Amir Mahmoodabadi2, Ali Bahrami-Samani1,
Amir R. Jalilian1, Mohammad Mazidi1, Hossein Afarideh1,
Mohammad Ghannadi-Maragheh1
1 Radiopharmaceutical Research and Development
Laboratory (RRDL),
Nuclear Science and Technology Research Institute (NSTRI),
14155-1339, Tehran, Iran
2 Faculty of Nuclear Engineering and Physics, Amirkabir University of Technology,
P. O. Box 15875-4413, Tehran, Iran
The preparation of 165Dy-labeled chitosan for radiosynovectomy applications is described in this paper. 165Dy (T1/2 = 2.33 h) was prepared by irradiation of natural Dy(NO3)3 at a flux of 3–4 × 1013 neutrons/cm2.s for about
6 h. The irradiation resulted in the production of 11.1 GBq (300 mCi) of 165Dy activity. Emitting gamma ray (94.7 keV) and beta particles (Emax = 1.3 MeV, 83%) 165Dy decays to 165Ho. Eight hours after bombardment, the corresponding specific activity was 703 MBq/mg (19 mCi/mg). The irradiated target was dissolved in 0.1 N HCl solution. Radionuclidic purity was ascertained by high resolution gamma spectrometry. Chitosan solution was prepared in acetic acid solution (pH 3). The chitosan solution was labeled with 165Dy to prepare 165Dy-chitosan (165Dy-Chit) complex (labeling yield,
> 99% and specific activity ~ 3.7 TBq/mmol). In optimized conditions (pH 3, 35 mg/4 ml chitosan acidic solution, and
370 MBq of 165Dy) Chit was stable after 48 h. Bioevaluation of the prepared 165Dy-Chit was carried out by injecting
37 MBq (1 mCi, 50–100 µl) directly into the knee joints of wild rats. Free 165Dy cation was also injected to study the effect of complex formation on the retention of radionuclide in the administered site. To study the consequence of radioactivity leakage from the administration site, a dilute sample of the complex was injected intravenously into the rats followed by biodistribution studies. It was observed that there was no significant extra-articular leakage of the injected activity over the study period of 24 h post-injection.
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