TY - JOUR T1 - Synthesis and In Vivo Evaluation of <em>p</em>-<sup>18</sup>F-Fluorohippurate as a New Radiopharmaceutical for Assessment of Renal Function by PET JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 147 LP - 153 DO - 10.2967/jnumed.110.075895 VL - 52 IS - 1 AU - Vibhudutta Awasthi AU - Gopal Pathuri AU - Hrushikesh B. Agashe AU - Hariprasad Gali Y1 - 2011/01/01 UR - http://jnm.snmjournals.org/content/52/1/147.abstract N2 - The molecular structure of p-18F-fluorohippurate (18F-PFH) is similar to that of p-aminohippurate, a gold standard for the measurement of effective renal plasma flow. The objective of this study was to investigate 18F-PFH as a new PET renal agent. Methods: 18F-PFH was synthesized by reacting N-succinimidyl-4-18F-fluorobenzoate (18F-SFB) with glycine at 90°C (pH 8) for 20 min. In vitro stability was determined by incubating 18F-PFH in fresh human plasma at 37°C for 60 min. In vivo stability was determined by high-performance liquid chromatography analysis of urine collected from a normal rat at 40 min after injection of 18F-PFH. The plasma protein binding and erythrocyte uptake were determined using plasma collected from a normal rat at 5 min after injection of 18F-PFH. The plasma clearance of 18F-PFH was determined using a single-injection clearance method in normal and probenecid-treated rats. Biodistribution studies were conducted in normal rats at 10 min and 1 h after injection of 18F-PFH. Dynamic PET/CT studies were conducted in normal rats injected with 18F-PFH. Results: In normal rats, the plasma clearance of 18F-PFH was 4.11 ± 1.09 mL/min/100 g, which reduced by approximately 50% (P = 0.03) to 2.01 ± 0.08 mL/min/100 g in probenecid-treated rats. About 45.3% of 18F-PFH was found to associate with plasma proteins in vivo in normal rats. Biodistribution studies of 18F-PFH in normal rats showed 72.1 ± 6.4 percentage injected dose and 88.6 ± 6.2 percentage injected dose, respectively, in urine at 10 min and 1 h after injection. The uptake in other organs was negligible. High-performance liquid chromatography analysis of urine collected from a rat at 40 min after injection of 18F-PFH indicated that it was excreted intact, with no metabolic products. Dynamic PET revealed a rapid clearance of 18F-PFH through the renal–urinary pathway. The PET-derived renograms revealed a time to peak activity of 3.0 ± 1.0 min. Conclusion: These combined results warrant further investigation of 18F-PFH as a radiopharmaceutical for the assessment of renal function by PET. ER -