Strong Iodine Tincture
» Strong Iodine Tincture contains, in each 100 mL, not less than 6.8 g and not more than 7.5 g of iodine (I), and not less than 4.7 g and not more than 5.5 g of potassium iodide (KI).
Strong Iodine Tincture may be prepared by dissolving 50 g of Potassium Iodide in 50 mL of Purified Water, adding 70 g of Iodine, and agitating until solution is effected, and then adding Alcohol to make the product measure 1000 mL.
Packaging and storage— Preserve in tight, light-resistant containers.
Identification—
A: Add 1 drop to a mixture of 1 mL of starch TS and 9 mL of water: a deep blue color is produced.
B: Evaporate a few mL on a steam bath to dryness: the residue responds to the flame test for Potassium 191 and to the tests for Iodide 191.
Alcohol content 611: between 82.5% and 88.5% of C2H5OH.
Assay for iodine— Proceed as directed in the Assay for iodine under Strong Iodine Solution, using 10 mL of Strong Iodine Tincture.
Assay for potassium iodide— Proceed as directed in the Assay for potassium iodide under Strong Iodine Solution, using 10 mL of Strong Iodine Tincture. The difference between the number of mL of 0.05 M potassium iodate used and half the number of mL of 0.1 N sodium thiosulfate used in the Assay for iodine, multiplied by 16.60, represents the number of mg of KI in the volume of Strong Iodine Tincture taken.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Behnam Davani, Ph.D., M.B.A.
Senior Scientist
1-301-816-8394
(MDAA05) Monograph Development-Antivirals and Antimicrobials
USP32–NF27 Page 2652