Soft soap, Sapo Viridis or Green Soap, is prepared by heating olive oil with potassium hydroxide and water, and allowing the mixture to cool. It occurs as a yellowish-green, sometimes yellowish-white or yellowish-brown, almost odourless, plastic, and unctuous mass, and is usually transparent. The tint of soft soap depends on the olive oil employed in making it, but copper compounds and chlorophyll are sometimes added to produce an artificial green colour. Hence the B.P. test against copper. Sapo Mollis, U.S.P., is made from linseed oil (see Sapo Kalinus).
Soluble in water (1 in 4), yielding a clear or nearly clear solution; it is more soluble in boiling water (1 in 1), and almost entirely soluble in alcohol (1 in 1).
Constituents.—This soap consists chiefly of potassium oleate, but also contains the glycerin formed in making it.
Action and Uses.—Soft soap is employed in the preparation of various liniments, its solution in dilute alcohol forming a suitable lubricant for rubbing sprains and bruises. A strong solution in alcohol (2 parts in 3) is much used as a liquid shampoo to cleanse the scalp previous to the application of antiseptic lotions. Such a solution is also employed by surgeons to cleanse the skin, or an ethereal solution of soft soap may be used. Soft soap is used to remove incrustations in chronic, scaly, skin diseases, such as psoriasis. A solution (1 in 30 to 40 of warm water) is employed as a rectal enema to remove impacted faeces.
- Enema Saponis, B.P.C.—ENEMA OF SOAP.
- Soft Soap, 2.5; water, warm, to 100. This enema is used to evacuate the bowel, the quantity sufficient for one enema being 600 mils (20 fluid ounces).
- Linimentum Saponis, B.P.—LINIMENT OF SOAP. Syn.—Soap Liniment; Opodeldoc.
- Soft soap, 4; camphor, 2; oil of rosemary, 0.75; alcohol, 32; distilled water, 8. Dissolve the camphor and oil in the alcohol, add the soap and distilled water, shake until dissolved, and filter after allowing to stand for seven days. Liniment of soap is a mild counter-irritant, used to rub sprains, contusions, and rheumatic joints, and to dilute more active liniments.
- Liquor Saponis Aethereus, B.P.C.—ETHEREAL SOAP SOLUTION. Syn.—Ether Soap.
- Oleic acid, 35; potassium hydroxide solution, saturated, a sufficient quantity alcohol, 15; oil of lavender, 0.2; methylated ether (specific gravity, 0.720), sufficient to produce 100. Should be kept in well-stoppered bottles. It is used to cleanse skin areas before surgical operations. A small quantity should be well rubbed in until the surface is dry, then, with a brush and hot water, thoroughly scrub the skin. The ether, being a fat solvent, penetrates the epidermis and carries the soap with it. The detergent action of this solution may be increased by using a slight excess of potash.
- Liquor Saponis Antisepticus, B.P.C.—ANTISEPTIC SOAP SOLUTION. Syn.—Antiseptic Ethereal Soap.
- Mercuric iodide, 0.05; potassium iodide, 0.51; ethereal soap solution, to 100.
- Spiritus Saponatus, B.P.C.—SOAP SPIRIT. 65 in 100.
- A detergent solution for use as a shampoo. It maybe perfumed with lavender or other oil, and such antiseptics as thymol, naphthol or mercury biniodide may be added if necessary. Spiritus Saponatus of the German Pharmacopoeia is prepared by saponifying 6 by weight of olive oil with 7 by weight of solution of potash (specific gravity, 1.138 to 1.140), and adding 30 by weight of alcohol and 17 of water.
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.