Background: Rheumatoid arthritis (RA) is an inflammatory chronic disease characterized
by inflammation, pain, swelling and disability, and radiosynovectomy is one of the disease
treatment lines. In this study, the possibility of providing rhenium-186/rhenium-188 chitosan radiopharmaceuticals,
optimization of conditions for their production and bio-distribution are reported.
Objective: In order to build perrhenic acid for labeling, natural rhenium was exposed to radiation.
Radionuclidic and radiochemical purities of (186/188Re)-NaReO4 were examined by gamma spectroscopy
and paper chromatography methods, respectively.
Methods: Labeling of chitosan with rhenium was done in different acidic situations. The radiochemical
purity 186/188Re-chitosan was applied by radio thin layer chromatography (RTLC). Lastly,
the bio-distribution of the radiolabeled chitosan was studied in various organs after intra articular
injection of the complex to lab rats. Gamma spectrometry confirmed the high rhenium radionuclidic
purity. Chromatography results showed that perrhenic acid was produced with purity greater
than 97% and rhenium chitosan labeling was done over 98% in pH = 3. Dissection results showed
a high bio-distribution of 186/188Re-chitosan after injection into the joint with no leakage to surrounding
Conclusion: According to the results, there is a possibility of labeling rhenium with chitosan in
very high radiochemical purity. Regarding the high retention of these radiopharmaceuticals in
joints with no leakage to surrounding organs, 186/188Re-chitosan can be applied as new radiosynovectomy
drugs for rheumatoid arthritis treatment.