Radiosynthesis and in vivo evaluation of a fluorine-18 labeled pyrazine based radioligand for PET imaging of the adenosine A2B receptor.
Bioorg Med Chem
; 26(16): 4650-4663, 2018 09 01.
Article
in En
| MEDLINE
| ID: mdl-30104122
On the basis of a pyrazine core structure, three new adenosine A2B receptor ligands (7a-c) were synthesized containing a 2-fluoropyridine moiety suitable for 18F-labeling. Compound 7a was docked into a homology model of the A2B receptor based on X-ray structures of the related A2A receptor, and its interactions with the adenosine binding site were rationalized. Binding affinity data were determined at the four human adenosine receptor subtypes. Despite a rather low selectivity regarding the A1 receptor, 7a was radiolabeled as the most suitable candidate (Ki(A2B)â¯=â¯4.24â¯nM) in order to perform in vivo studies in mice with the aim to estimate fundamental pharmacokinetic characteristics of the compound class. Organ distribution studies and a single PET study demonstrated brain uptake of [18F]7a with a standardized uptake value (SUV) of ≈1 at 5â¯min post injection followed by a fast wash out. Metabolism studies of [18F]7a in mice revealed the formation of a blood-brain barrier penetrable radiometabolite, which could be structurally identified. The results of this study provide an important basis for the design of new derivatives with improved binding properties and metabolic stability in vivo.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pyrazines
/
Contrast Media
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Radiopharmaceuticals
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Receptor, Adenosine A2B
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Positron-Emission Tomography
Type of study:
Prognostic_studies
Limits:
Animals
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Female
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Humans
Language:
En
Journal:
Bioorg Med Chem
Journal subject:
BIOQUIMICA
/
QUIMICA
Year:
2018
Document type:
Article
Affiliation country:
Germany
Country of publication:
United kingdom