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Synthesis and in vivo evaluation of both (2R,3R)-[123I]- and (2S,3S)- -[123I]-trans-2-hydroxy-5-((E)-3-(iodo) allyloxy)-3-(4-phenyl-1-piperazinyl) tetralin as SPECT radiotracer

Assaad T., Al Rayyes A. H.

Nukleonika

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2013

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Vol. 58, No. 2

261--267

EN

We report the synthesis of enantiopure benzovesamicol derivatives: (2R,3R)-[123I]-trans-2-hydroxy-5-((E)-3- -(iodo)allyloxy)-3-(4-phenyl-1-piperazinyl) tetralin and (2S,3S)-[123I]-trans-2-hydroxy-5-((E)-3-(iodo)allyloxy)-3-(4- phenyl-1-piperazinyl) tetralin; [(2R,3R)-[123I]-1 and (2S,3S)-[123I]-1]. Both compounds were obtained with radiochemical and optical purities greater than 97% and with radiochemical yields in the range of 50–60%. To determine whether these compounds could have potential advantage compared to [125I]-iodo benzovesamicol (IBVM), IBVM was also labelled and used as the reference compound in all in vivo experiments. Both (2R,3R)-[123I]-1 and (-)-[125I]-IBVM showed similar time activity curves (TACs) with the highest accumulations in the striatum region followed by the cortex, hippocampus and then cerebellum. While (2S,3S)-[123I]-1 showed an overall homogeneous brain distribution. However, time activity curves of (2R,3R)-[123I]-1 confirmed that this compound could be used to visualize the vesicular acetylcholine transporter (VAChT) in vivo, at each point of the kinetic study. Also (2R,3R)-[123I]-1 showed lower specific bindings compared to [125I]-IBVM. These results suggested that (2R,3R)-[123I]-1 is inferior in comparison with [125I]-IBVM for in vivo VAChT exploration.

2

Synthesis and biodistribution of both (±)-5-[ 18F]-fluoroethoxy and (±)-5-[ 18F]-fluoropropoxy piperazine analogs of benzovesamicol as vesicular acetylcholine transporter ligands (VAChT)

Assaad T., Al Rayyes A. H.

Nukleonika

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2013

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Vol. 58, No. 2

269--274

EN

The radiosynthesis and preliminary biological evaluation in rats’ brain of two novel piperazine analogs of benzovesamicol as ligands for the vesicular acetylcholine transporter (VAChT) have been carried out. The novel benzovesamicol derivatives 5-(2-fluoroethoxy)-3-(4-phenylpiperazin-1-yl)-1,2,3,4-tetrahydronaphthalen-2-ol and 5-(3-fluoropropoxy)-3-(4-phenylpiperazin-1-yl)-1,2,3,4-tetrahydronaphthalen-2-ol [(±)-[18F]-6 and (±)-[18F]-7] were successfully labelled with fluorine-18 from their tosylate precursors, with radiochemical purities greater than 98% and with radiochemical yield in the range of 5–6%. To determine whether these compounds could have potential advantage compared to [125I]-iodo benzovesamicol (IBVM), IBVM was also labelled and used as the reference compound in all in vivo experiments. Both (±)-[18F]-6 and (±)-[18F]-7 showed lower specific binding in all brain areas explored 2 h post injection when compared to reference compound (-)-[125I] IBVM. Furthermore, defluorination indicated that (±)-[18F]-6 and (±)-[18F]-7 are not suitable as radioligands to explore the VAChT in vivo by PET. Moreover, it is well known that interaction at the VAChT binding site is enantioselective, and therefore, working with enantiomerically pure compounds, could improve the compound activity.

3

Radiosynthesis and biological evaluation of 123I-(±)-trans-2-hydroxy-5-((E)- -3-(iodo)allyloxy)-3-(4-phenyl-1-piperazinyl) tetralin

Assaad T., Al Rayyes A. H.

Nukleonika

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2012

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Vol. 57, No. 1

75-80

XX

This work reports both the radiolabeling and preliminary biodistribution results in the rat brains of (±)-[123I]- -II. The novel benzovesamicol derivative (±)-[123I]-II was successfully labeled with iodine-123 from its corresponding n-tributyltin, with radiochemical purity greater than 97% and radiochemical yield in the range 50–55%. (±)-[123I]-II showed a higher accumulation in striatum than in the other regions studied. To determine if (±)-[123I]-II could provide an advantage compared to reference compound [125I]-IBVM a kinetic study was carried out, at each point of the kinetic study, (±)-[123I]-II showed a lower specific binding compared to [125I]-IBVM. Time activity curves of (±)-[123I]-II confirmed that this compound is inferior to [125I]-IBVM to explore the VAChT in vivo by SPECT. Moreover, it is well known that interaction at the VAChT binding site is enantioselective, and therefore, working with enantiomerically pure compounds, could improve the compound activity.

4

Routine simultaneous production of no-carrier-added high purity 64Cu and 67Ga

Al Rayyes A. H., Ailouti Y.

Nukleonika

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2011

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Vol. 56, No. 4

259-262

EN

A routine production method of no-carrier-added 64Cu was performed. A copper target support is electroplated by gold then an optimized thickness of enriched 68Zn layer is deposited. The 68Zn target was bombarded with a 23.5 MeV and 250 miA proton beam, generating the main nuclear reactions 68Zn(p,2n)67Ga and 68Zn(p,alfa n)64Cu. A semi-automated separation method using a chromatographic column system was developed for 64CuCl2 production. A 600 mCi batch of 64Cu is produced at the end of separation and purification chemistry. The radionuclidic purity of 64Cu was less than 98% as required by the United States and European Pharmacopoeias. Radiochemical purity and activity concentration is suitable for labeling different ligands to produce diagnostic and therapeutic radiopharmaceuticals.

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Enriched water-H2 18 O purification to be used in routine 18FDG production

Al Rayyes A. H.

Nukleonika

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2010

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Vol. 55, No. 3

401-405

EN

18O-water obtained from an 2-deoxy-2-[18F]-fluoro-D-glucose (18FDG, Synthera) synthesis unit is used for purification. The purification process consists of ultraviolet (UV) irradiation followed by a distillation in a preevacuated system. After purification, the loss of enriched water was about only 5 per cent. Organic compounds, radioisotopes, trace metals and gases are eliminated efficiently. Results show that there is no significant difference in the production yield of 2-deoxy-2-[18F]-fluoro-D-glucose ([18F]FDG) whether using purified enriched water by the proposed method of purification or using the new enriched water. This method offers the necessary precaution from contamination by tritium during the purification process. The obtained 18FDG or Na-18F using the purified 18O-water is of tritium free.