131I-trazodone: preparation, quality control and in vivo biodistribution study by intranasal and intravenous routes as a hopeful brain imaging radiopharmaceutical

Publication date: Available online 27 April 2017
Source:Revista Española de Medicina Nuclear e Imagen Molecular
Author(s): M.A. Motaleb, I.T. Ibrahim, M.E. Sayyed, G.A.S. Awad
ObjectivesThe preparation of ¹³¹I-trazodone hydrochloride and its biological evaluation as a promising brain imaging radiopharmaceutical using two routes of administration.Material and methodsTrazodone (TZ) was radiolabelled with ¹³¹I using direct electrophilic substitution, and different factors affecting labelling yield were studied. Quality control of ¹³¹I-TZ was carried out using ascending paper chromatography, paper electrophoresis, and high pressure liquid chromatography (HPLC). In vivo biodistribution of ¹³¹I-TZ was evaluated in Swiss albino mice using 3 methods: intravenous ¹³¹I-TZ solution (IVS), intranasal ¹³¹I-TZ solution (INS), and intranasal ¹³¹I-TZ microemulsion (INME).ResultsOptimum labelling yield of 91.23±2.12% was obtained with in vitro stability of ¹³¹I-TZ up to 6h at room temperature. The biodistribution results showed a notably higher and sustained brain uptake for INME compared to IVS and INS at all time intervals. In addition, heart and blood uptake levels for INME were lower than those for IV solution which, in turn, could decrease the systemic side effects of trazodone. Also, the ¹³¹I-trazodone INME brain uptake of 6.7±0.5%ID/g was higher than that of ^99mTc-ECD and ^99mTc-HMPAO (radiopharmaceuticals currently used for brain imaging).Conclusion^131/123I-trazodone formulated as INME could be used as a promising radiopharmaceutical for brain imaging.



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