PMID: 7735484Jan 20, 1995Paper

Quantification of an 11C-labelled beta-adrenoceptor ligand, S-(-)CGP 12177, in plasma of humans and rats

Journal of Chromatography. B, Biomedical Applications
A van WaardeW Vaalburg

Abstract

beta-Adrenoceptors in human lungs and heart can be imaged with the radioligand 4-[3-[(1,1-dimethylethyl)amino]-2-hydroxypropoxy]-1,3- dihydro-2H-benzimidazol-2-11C-one (CGP 12177, [11C]I). For quantification of receptor density with compartment models by adjustment of rate constants, an 'input function' is required which consists of the integral of the concentration of unmodified ligand in arterial plasma over time. A discrepancy in the literature regarding metabolic stability of [11C]I prompted us to study metabolism in rats by reversed-phase HPLC (RP-HPLC) of trichloroacetic acid extracts of arterial plasma after i.v. injection of [11C]I (> 11.1 TBq/mmol, 11 MBq/kg). Some plasma samples were also directly applied to an internal-surface reversed-phase (ISRP) column. In parallel experiments, tritiated [11C]I was employed and methanol extracts of arterial plasma were analyzed by straight-phase TLC. The three methods were in excellent agreement. Unmodified [11C]I decreased from > 98.5% (3H) or > 99.9% (11C) initially to 57 +/- 7% at 80 min post injection due to formation of two polar metabolites. Using the RP-HPLC method, no metabolism was detectable in humans up to 30 min after injection of [11C]I (1851 MBq). Deproteinization of...Continue Reading

References

Oct 1, 1992·International Journal of Radiation Applications and Instrumentation. Part B, Nuclear Medicine and Biology·A van WaardeK I Lie
Feb 1, 1985·Proceedings of the National Academy of Sciences of the United States of America·H AffolterM Staehelin
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Citations

May 7, 1998·European Journal of Pharmacology·A van WaardeW Vaalburg
May 17, 2000·Pharmaceutica acta Helvetiae·V W PikeP G Camici
Oct 1, 2003·Clinical Positron Imaging : Official Journal of the Institute for Clinical P.E.T·Philip H. ElsingaWillem Vaalburg
Sep 2, 2006·Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan·Ken-ichi Nishijima
Dec 22, 2012·Se pu = Chinese journal of chromatography·Xiaoyu WuXianhua Wang

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