Zinc Sulphate Lotion
Zinc Sulfate Cutaneous Solution
DEFINITION
Zinc Sulfate Lotion is a cutaneous solution. It contains 1% w/v of Zinc Sulfate Heptahydrate in a suitable aqueous vehicle.
The lotion complies with the requirements stated under Liquids for Cutaneous Application and with the following requirements.
Content of zinc sulfate heptahydrate, ZnSO4,7H2O
0.95 to 1.05% w/v.
ASSAY
To 20 mL add 25 mL of 0.1M hydrochloric acid and 0.1 g of activated charcoal, shake, filter and wash the residue with 100 mL of 0.01M hydrochloric acid. To the combined filtrate and washings add 5 mL of ammonia buffer pH 10.9 and titrate with 0.05M disodium edetate VS using mordant black 11 solution as indicator. Repeat the procedure using 20 mL of water in place of the preparation being examined. The difference between the titrations represents the amount of disodium edetate required. Each mL of 0.05M disodium edetate VS is equivalent to 14.38 mg of ZnSO4,7H2O.
