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C10H11I2NO3 447.01

1(4H)-Pyridineacetic acid, 3,5-diiodo-4-oxo-, propyl ester.
Propyl 3,5-diiodo-4-oxo-1(4H)pyridineacetate [587-61-1].
» Propyliodone contains not less than 99.0 percent and not more than 101.0 percent of C10H11I2NO3, calculated on the dried basis.
Packaging and storage— Preserve in tight, light-resistant containers. Store at 25, excursions permitted between 15 and 30.
A: Heat 100 mg with a few drops of sulfuric acid: violet vapors are evolved.
B: Reflux 1 g with 10 mL of 1 N sodium hydroxide for 30 minutes, add 10 mL of water, and acidify to litmus paper with hydrochloric acid: the precipitate of 3,5-diiodo-4-oxo-1(4H)-pyridineacetic acid, after being washed with water and dried at 105, melts at about 245.
Melting range 741: between 187 and 190.
Acidity— Dissolve 1.0 g in 40 mL of hot n-propyl alcohol previously neutralized to phenolphthalein TS, cool, and allow to stand in an ice bath for 15 minutes with frequent shaking. Filter, wash the residue with neutralized n-propyl alcohol, combine the filtrate and washings, add phenolphthalein TS, and titrate with 0.050 N sodium hydroxide to a pink color that persists for 15 seconds: not more than 0.15 mL of 0.050 N sodium hydroxide is required for neutralization.
Loss on drying 731 Dry it at 105 to constant weight: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Iodine and iodide— Shake 2.4 g with 30 mL of water for 15 minutes, filter, and to 10 mL of filtrate add 1 mL of 2 N nitric acid, 1 mL of sodium nitrite solution (1 in 500), and 2 mL of chloroform. Shake, and centrifuge: any purple color in the chloroform layer is not darker than that obtained with a mixture of 6 mL of water and 4 mL of potassium iodide solution (2.6 in 100,000) treated in the same manner (0.01% of I).
Assay— Using about 15 mg of Propyliodone, accurately weighed, proceed as directed in the Assay under Iodoquinol. Each mL of 0.02 N sodium thiosulfate is equivalent to 0.7450 mg of C10H11I2NO3.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Ian DeVeau, Ph.D.
Director, Veterinary Drugs and Radiopharmaceuticals
(RMI05) Radiopharmaceuticals and Medical Imaging Agents 05
USP32–NF27 Page 3433
Pharmacopeial Forum: Volume No. 29(6) Page 1976