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Title: 21-(/sup 18/F)fluoro-16 alpha-ethyl-19-norprogesterone: synthesis and target tissue selective uptake of a progestin receptor based radiotracer for positron emission tomography

Journal Article · · J. Med. Chem.; (United States)
DOI:https://doi.org/10.1021/jm00402a019· OSTI ID:7125966

We have synthesized 21-(/sup 18/F)fluoro-16 alpha-ethyl-19-norprogesterone (FENP), a high affinity ligand for the progesterone receptor, labeled with the positron-emitting radionuclide fluorine-18 (t1/2 = 110 min). The synthesis proceeds in two steps from 21-hydroxy-16 alpha-ethyl-19-norprogesterone and involves (/sup 18/F)fluoride ion displacement of the 21-trifluoromethanesulfonate (21-triflate). This material is purified by HPLC and is obtained in 4-30% overall yield (decay corrected) within 40 min after the end of bombardment to produce (/sup 18/F)fluoride ion. The effective specific activity, determined by competitive radioreceptor binding assays, is 700-1400 Ci/mmol. In vivo, (/sup 18/F)FENP demonstrates highly selective, receptor-mediated uptake by the uterus of estrogen-primed rats; the uterus to blood and uterus to muscle ratios were respectively 26 and 16 at 1 h and 71 and 41 at 3 h after injection. The high target tissue selectivity of this uptake suggests that this compound may be useful for the in vivo imaging of progestin target tissues and receptor-rich tumors (such as human breast tumors) by positron emission tomography.

Research Organization:
Univ. of Illinois, Urbana (USA)
OSTI ID:
7125966
Journal Information:
J. Med. Chem.; (United States), Vol. 31:7
Country of Publication:
United States
Language:
English