Volatile Liniment

VOLATILE LINIMENT, Linimentum volatile, Linimentum ammoniatum, a mixture of easily saponifiable fatty oil with ammonia (spirits of hartshorn). According to Formula VII, volatile liniment is a mixture of 3 parts sunflower oil with 1 part spirits of hartshorn containing 10% NH₃. Due to the difficult saponification of sunflower oil, this mixture is unstable and separates into two layers when left standing. Like other liniments, volatile liniment is an oil-in-water emulsion, maintained in fine dispersion by ammonium soap formed due to the presence of some free fatty acids in the oil. The stability of the emulsion can be increased by replacing part of the oil with oleic acid or easily saponifiable coconut oil. Solidified liniment is thinned (Formula VII) with a small amount of 90% alcohol. It is recommended to prepare volatile liniment for short-term use only. - The action of volatile liniment consists of the irritating effect of ammonia, slightly neutralized by the effect of the fat. It is used only externally as a local irritant and counter-irritant for rubbing. - To volatile liniment can be added substances soluble in oil, e.g. up to 10% camphor, menthol, essential oils, a small amount (5%) of chloroform, etc. The addition of substances soluble in water (potassium iodide) or reacting with ammonia (iodine, tincture of iodine, salicylic acid, etc.) is not recommended as pointless: these substances are not absorbed through intact skin and only disrupt the stability of the volatile liniment.