ortho-Iodohippuric acid (ortho-iodohippurate, OIH) is an analog of p-aminohippuric acid for the determination of effective renal plasma flow. Labelled OIH has a significantly higher clearance than other radiopharmaceutical yet developed and is eminently suitable for renography. It is eliminated mainly by tubular secretion. In patients with normally functioning kidneys, 85% of the OIH may be found in the urine 30 minutes after intravenous injection.
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| Other names | Iodohippuric acid, I Hippuran, I OIH, I-Hippuran, I-OIH, Iodobenzoylglycine, Sodium iodohippurate, Sodium o-iodohippurate, ortho' Iodohippurate, ortho-Iodohippurate, Orthoiodohippurate, Radio Hippuran, Radio-Hippuran, RadioHippuran, Sodium Iodohippurate [1] |
| Routes of administration | intravenous |
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| Excretion | renal |
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| ECHA InfoCard | 100.005.176 |
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| Formula | C9H8INO3 |
| Molar mass | 305.071 g·mol−1 |
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OIH was first labelled with 131I by Tubis and colleagues (Tubis, Posnick and Nordyke in 1960) and for many years this was the only radiopharmaceutical for renography. 131I has a half-life of 8 days and emits high-energy γ rays (364 keV) in addition to β particles. These physical characteristics were acceptable for probe studies when quantities of the order 1-2 MBq (25-50 μCi) were administered, but they are far from ideal for γ-camera studies which demand a higher activity and a γ ray emission of lower energy. The introduction of OIH labelled with 123I, with its short physical half-life (13 hours) and its gamma emission of 159 keV has greatly improved the diagnostic potential of renal studies by combining the production of high-quality functional images with the ability to derive a renogram. The only factor limiting its widespread use is restricted availability and the expense involved in its cyclotron production.[2]
References edit
- ^ Pubchem. "Compound Summary for CID 8614: 2-Iodohippuric acid". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ^ Testa HJ (22 October 2013). "Radiopharmaceuticals". In O'Reilly PH, Shields RA, Testa HJ (eds.). Nuclear Medicine in Urology and Nephrology (2nd ed.). Butterworth-Heinemann. p. 239. ISBN 978-1483162416.