Carbamide Peroxide Topical Solution
» Carbamide Peroxide Topical Solution is a solution in anhydrous glycerin of Carbamide Peroxide or of carbamide peroxide prepared from hydrogen peroxide and Urea. It contains not less than 78.0 percent and not more than 110.0 percent, by weight, of the labeled amount of CH6N2O3.
Packaging and storage— Preserve in tight, light-resistant containers, and avoid exposure to excessive heat.
A: Mix 1 mL with 1 mL of nitric acid: a white, crystalline precipitate is formed.
B: It responds to the tests for Peroxide 191.
Specific gravity 841: between 1.245 and 1.272.
pH 791: between 4.0 and 7.5.
Assay— Transfer an accurately weighed quantity of Topical Solution, equivalent to about 100 mg of carbamide peroxide, to a 500-mL iodine flask with the aid of 25 mL of water, add 5 mL of glacial acetic acid, and mix. Add 2 g of potassium iodide and 1 drop of ammonium molybdate TS, and allow to stand in the dark for 10 minutes. Titrate the liberated iodine 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 4.704 mg of CH6N2O3.
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Topic/Question Contact Expert Committee
Monograph Daniel K. Bempong, Ph.D.
Senior Scientist
(MDPS05) Monograph Development-Pulmonary and Steroids
USP32–NF27 Page 1788