Packaging and storage—
Preserve in tight, light-resistant containers, at a temperature not exceeding 35
.
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
Sodium 
191
and to the tests for
Iodide 191.
Assay for iodine—
Transfer 10.0 mL of Topical Solution into a glass-stoppered, 500-mL flask, and dilute with 10 mL of water. Titrate with 0.1 N sodium thiosulfate VS, adding 3 mL of
starch TS as the endpoint is approached. Each mL of 0.1 N sodium thiosulfate is equivalent to 12.69 mg of I.
Assay for sodium iodide—
Transfer 10.0 mL of Topical Solution to a glass-stoppered 500-mL flask, add 30 mL of water and 50 mL of hydrochloric acid, cool to room temperature, and titrate with 0.05
M potassium iodate VS until the dark brown solution that is produced becomes pale brown. Add 1 mL of amaranth TS, and continue the titration slowly until the red color just changes to yellow. 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 14.99, represents the number of mg of NaI in the volume of Topical Solution taken.
