Calamine Lotion

Calamine Cutaneous Suspension

Calamine Lotion is a cutaneous suspension.

Calamine	150 g
Zinc Oxide	50 g
Bentonite	30 g
Sodium Citrate	5 g
Liquefied Phenol	5 mL
Glycerol	50 mL
Purified Water, freshly boiled and cooled	Sufficient to produce 1000 mL

The following directions apply.

Triturate the Calamine, the Zinc Oxide and the Bentonite with a solution of the Sodium Citrate in about 700 mL of the Purified Water and add the Liquefied Phenol, the Glycerol and sufficient Purified Water to produce 1000 mL.

The lotion complies with the requirements stated under Liquids for Cutaneous Application and with the following requirements.

A. To 2 mL add 2 mL of periodic acid reagent, shake, centrifuge and add 0.5 mL of the supernatant liquid to 2 mL of ammoniacal silver nitrate solution in a test tube. Heat on a water bath at 70º for 5 minutes. A silver mirror is produced on the side of the tube.

B. Mix 2 mL with 50 mL of water, centrifuge and decant the supernatant liquid. Suspend the residue in 20 mL of water, add 1 mL of hydrochloric acid, mix and filter. 5 mL of the filtrate, after neutralisation by drop wise addition of 2m sodium hydroxide, yields the reaction characteristic of zinc salts, Appendix VI.

14.5 to 18.0% w/w when determined by the following method. Evaporate 5 g to dryness and ignite until, after further ignition, two successive weighings do not differ by more than 0.2% of the weight of the residue.