Sapo Kalinus. Potash Soap.
Synonym.—Linseed Oil Soap.
Potash soap may be prepared by the following process:—Heat 40 of linseed oil to about 70° on a water-bath, dissolve 9 of potassium hydroxide in 45 of water, heat the solution to 70°, and mix thoroughly with the oil; then add 4 of alcohol, mix, and continue the heat, without stirring (transferring to a sand bath, if necessary), until a small portion of the mixture is found to dissolve in boding water without the separation of oily drops. Finally, allow the product to cool, and transfer it to suitable vessels. Sapo Kalinus is official in the German Pharmacopoeia, and corresponds to Sapo Mollis, U.S.P. It occurs as a soft, unctuous, yellowish-brown mass, with a characteristic odour and an alkaline taste. The aqueous solution is nearly clear and shows an alkaline reaction to litmus. When dissolved in hot alcohol, not more than 3 per cent. of insoluble residue should remain.
Soluble in water (1 in 4), alcohol (1 in 1).
Action and Uses.—Potash soap is used in the preparation of liquid Soaps which are preferred by some surgeons to the preparations of green soft soap for use to cleanse the skin.
- Linimentum Saponis Mollis, U.S.P.—LINIMENT OF SOFT SOAP.
- Linseed oil soft soap, 65; oil of lavender, 2; alcohol (95 per cent.), sufficient to produce 100.
- Spiritus Saponis Kalini, B.P.C.—SPIRIT OF POTASH SOAP.
- Potash soap, 65; spirit of lavender, 3; alcohol, to 100. Used to cleanse the skin before operations (see also Liquor Saponis Aethereus). It resembles Linimentum Saponis Mollis, U.S.P. The linseed oil soap used is a more efficient detergent than the ordinary soft soap. Spiritus Saponis Kalini (Hebra) is prepared with equal weights of potash soap, spirit of lavender, and alcohol; Unna's spirit is prepared with 100 of potash soap, 7.5 by weight of oil of lavender, and 100 by weight of alcohol (95 per cent.).