title: Synthesis and in vivo evaluation of ortho-[(124)I]iodohippurate for PET renography in healthy rats.
abstract: Ortho-[(131)I]iodohippurate [(131)I]OIH (marketed as Hippuran I 131), a gold standard for radionuclide renography, and [(123)I]OIH were in clinical use for decades. Here we radiolabeled OIH with (124)I (a positron emitter) to combine the desirable biological properties of OIH and to enable the use of positron emission tomography (PET) for renography. [(124)I]OIH was synthesized with a slight modification to a previously reported method for the kit preparation of [(123)I]OIH based on the Cu(II) catalyzed isotope-exchange reaction. Our method utilized heating at 120°C under sealed condition in a heating block instead of autoclaving. [(124)I]OIH was obtained with a radiochemical purity of >99.3%, radiochemical yield of 94.5%, and specific activity of ~17 MBq/mg. Biodistribution studies in healthy Sprague Dawley rats revealed results comparable to that of [(131)I]OIH as reported in the literature. The PET-derived [(124)I]OIH renograms revealed an average time-to-peak of 2.8±0.4min and the average time-to-half-maximal activity of 11.4±1.5min, which are also comparable to that of [(131)I]OIH as reported in the literature. Results from this study indicate that the synthesis of [(124)I]OIH without using an autoclave and [(124)I]OIH PET renography are feasible.
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
authors.forename: Gopal
authors.initials: G
authors.lastname: Pathuri
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
authors.forename: Andria F
authors.initials: AF
authors.lastname: Hedrick
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
authors.forename: Vibhudutta
authors.initials: V
authors.lastname: Awasthi
authors.affiliation: Nephrology Section, Department of Internal Medicine, College of Medicine, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Cowley
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. Electronic address: hgali@ouhsc.edu.
authors.forename: Hariprasad
authors.initials: H
authors.lastname: Gali
mesh_terms: D000818:Animals; D007465:Iodohippuric Acid; D007668:Kidney / Q000000981:diagnostic imaging*; D011866:Radioisotope Renography; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution
chemical_list: D007465:Iodohippuric Acid
keywords: Hippuran; OIH; Ortho-iodohippurate; PET; Renography