Selenium Sulphide Scalp Application
Selenium Sulfide Application
Selenium Sulfide Cutaneous Suspension
DEFINITION
Selenium Sulfide Scalp Application is a cutaneous suspension of Selenium Sulfide in a suitable liquid basis.
The scalp application complies with the requirements stated under Liquids for Cutaneous Application and with the following requirements.
Content of selenium sulfide, SeS2
90.0 to 110.0% of the stated amount.
IDENTIFICATION
A. Gently boil a quantity containing 50 mg of Selenium Sulfide with 5 mL of nitric acid for 1 hour, dilute to 50 mL with water and filter. To 5 mL of the filtrate add 10 mL of water and 5 g of urea, boil, cool and add 2 mL of dilute potassium iodide solution. A yellow to orange colour is produced, which darkens rapidly on standing.
B. Allow the coloured solution obtained in test A to stand for 10 minutes and filter through kieselguhr. The filtrate yields the reactions characteristic of sulfates, Appendix VI.
TESTS
Acidity
pH, 4.0 to 5.5, Appendix V L.
ASSAY
To a quantity containing 0.15 g of Selenium Sulfide add 25 mL of fuming nitric acid, heat on a water bath for 2 hours, cool and dilute to 250 mL with water. To 25 mL of the solution add 10 g of urea and 25 mL of water, boil, cool, add 10 mL of dilute potassium iodide solution and 10 mL of chloroform and titrate immediately with 0.05M sodium thiosulfate VS using
starch mucilage, added towards the end of the titration, as indicator. Shake vigorously as the end point is approached.
Each mL of 0.05M sodium thiosulfate VS is equivalent to 1.789 mg of SeS2.
