The triglycerides of fats are mainly solids at ordinary temperatures and are chiefly composed of saturated fatty acid esters.

The triglycerides of fixed oils are mainly liquids at ordinary temperatures and are chiefly composed of unsaturated fatty acid esters.

Fixed oils are liable to become rancid, a change which may arise as a result of several different types of chemical reaction, including hydrolysis of the glycerides, oxidation of saturated fatty acids to ketones, and oxidation at double bonds of unsaturated fatty acids.

Foreign Pharmacopoeias; In Belg., Chil., Cz., Egyp., Ger., Jug., Mex., Nor., Span., .Sired., Swiss, and U.S. The U.S. includes the synonym Sweet Almond Oil.

A pale yellow oil with a slight odour and a bland nutty taste. It is expressed from the seeds of the bitter or the sweet almond, but mainly front the bitter variety. The residue from bitter almonds is used for the production of volatile bitter almond oil.

Slightly soluble in alcohol; miscible with benzene, chloroform, ether, and light petroleum. Wt per ml. 0�909 to 0�914 g.

Uses. Almond oil is nutritive and demulcent and may he administered in the form of an emulsion. Externally it is applied as an emollient for chapped hands. It is sometimes used in the preparation of cold creams, brilliantines, hair lotions, and other toilet articles.

Foreign Pharmacopoeias; In Chin., Dan., Egyp., Fr., Ger., Ind., Jap., Jug., Alex., Swed., Swiss, and U.S.

The fixed oil obtained from the seeds of Arachis hypogoea (Leguminosae). It is a pale yellow oil with a faint nutty odour and a bland nutty taste. Wt per ml. 0�911 to 0�915 g.

Slightly soluble in alcohol; miscible with carbon disulphide, chloroform, ether and light petroleum. It is sterilised by heating at 150˚C for one hour. On exposure to air it thickens very slowly and becomes rancid.

Uses. Arachis oil has properties similar to olive oil and is used for the same purposes. Ground nut oils should only be used for edible purposes if containing less than 1% of free fatty acids since little inactivation is then caused to carotene or vitamin A. The addition of an antoxidant such as ethyl gallate was found effective in delaying inactivation of vitamin A so long as the free fatty acid content of the oil was below a certain limit; as the free fatty acid content of the oil increased, the protection afforded by the antoxidant decreased.

K. Ramamurti and B. N. Banerjee, Indian J. med. Res., 1948, 36, 371.

Enem. Oleos. (Cape Hosp.). Oil Enema. Arachis oil 4 fl. oz., enema of soap to 20 fl. oz.

Dose: 4 to 16 ml. (60 to 240 minims). Doses of 30 ml. (1 fl. oz.) are often administered.

Foreign Pharmacopoeias: In all pharmacopoeias examined.

The fixed oil expressed from the seeds of Ricinus communis (Euphorbiaceae). It is a nearly colourless or pale yellow viscid oil with a slight odour and taste which is bland at first, but afterwards acrid and nauseating. Wt per ml. 0�953 to 0�964 g.

Soluble 1 in 2 of alcohol (90%); miscible with dehydrated alcohol, chloroform, ether, and glacial acetic acid. It is sterilised by heating at 150˚C for 1 hour. Store in well-filled containers in a cool place.

Miscibility with alcohol and water. A phase diagram for castor oil, alcohol (95%) and water is given-M. R. Loran and E. P. Guth, J. Amer. pharm. Ass., Sci. Edn, 1951, 40, 465.

The purgative action of castor oil is due to the fatty acids (present as triglycerides) of which ricinoleic acid is the principal member.

The seeds, but not the oil, contain the poisonous protein, ricin; the 'press cake', therefore, is poisonous.

Uses. A mild purgative, especially valuable in acute diarrhoea, particularly when due to food poisoning. Small repeated doses of 0�3 to 0�6 ml. (5 to 10 Minims) may be given for the intestinal colic of children. Castor oil is a soothing application to the conjunctiva and allays irritation due to foreign bodies in the eye and it is also employed for making solutions of alkaloidal bases for ophthalmic purposes. It is sometimes applied externally, usually mixed with other emollients, in the treatment of bed-sores. It is often used as an ingredient of spirituous hair lotions.

Aromatic Castor Oil (U.S.N.F.). Cinnamon oil (U.S.P.) 0�3 ml., clove oil 1�1 ml., saccharin 50 mg., vanillin 100 mg., coumarin 10 mg., alcohol 3 ml., castor oil to 100 ml. Usual dose: 15 mil. (0.5 fl. oz.). A similar preparation Was included in the B.P.C. 1934

Castor Oil Capsules (U.S.N.F.). Usual strengths: 0�6, 1, 1�25, 2�5, and 5 ml.

Castor Oil Enemas. For softening impacted faeces. (1) Castor oil 10%, v/v in a 5% w/v solution of !oft soap; dose: 600 ml. (20 fl. oz.). (2) Castor oil 20% v/v in mucilage of starch or olive oil: dose: 300 ml. (10 fl. oz.).

Castor Oil Mixture (Ind. P.C., B.P.C. 1934) Mist. Ol. Ricin. Castor oil 37.5 ml., acacia 10 g., orange flower water I5 ml., cinnamon water to 100 ml. Dose: 30 to 60 ml. (I to 2 fl. oz.), as a single draught.

Mist. Ol. Ricin. Mit. (Cape Hosp.) Castor oil 5 m., arachis oil 10 m., powdered acacia 4 gr., concentrated orange flower water 2.5 m., elixir of saccharin 0.25 m., spirit of vanillin (1 in 80) 0.5 m., chloroform water to 60 m.

Oily Ophthalmic Vehicle (A.P.F.). Castor oil, heated at I50˚ for 1 hour and cooled. Suitable for preparing oily solutions of alkaloids.

Foreign Pharmacopoeias. In Chin., Egyp., Mex., and U.S. Also in Ind. P.C.

The refined fixed oil expressed from the seeds of the cotton plant, Gossypium herbaceum, and other species of Gossypium (Malvaceae). It is a pale yellow or yellow, odourless or nearly odourless oil with a bland nutty taste. Wt per ml. 0�915 to 0�920 g.

Slightly soluble in alcohol; miscible with chloroform, ether, and light petroleum. It is sterilised by heating at 150˚ for 1 hour. At temperatures below 12˚ particles of solid fat separate from the oil and at temperatures between 0˚ and 5˚ it congeals; the oil should be remelted and thoroughly mixed before any of it is used.

Uses. It has properties similar to olive oil and is used for the same purposes.

Foreign Pharmacopoeias; In Belg,., Chil., Chin., Cz., Dan., Egyp., Ger., Hung., Ind., Jap., Jug., Nor., Pol., Span., Swed., and Swiss. Also in U.S.N.F.

The fixed oil expressed from linseed and subsequently clarified. It is a yellowish-brown oil with a faint odour and a bland unpleasant taste, thickening on exposure to air and forming, when spread in a thin film, a hard transparent varnish. Wt per ml. 0�924 to 0�934 g. Much commercial oil has a marked odour and an acrid taste.

Soluble 1 in 40 of dehydrated alcohol; slightly soluble in alcohol; miscible with carbon disulphide, chloroform, ether, light petroleum, and turpentine oil.

Uses. Linseed oil is laxative in doses of 15 to 30 ml. (0.5 to 1 fl. oz.) but is rarely given internally because of its disagreeable taste. In veterinary medicine it is used as a laxative for horses and cattle.

Boiled linseed oil ('boiled oil') is linseed oil heated with litharge, magnesium resinate, or other 'driers', causing the oil to dry more rapidly. It must not be used for medicinal purposes.

The fixed oil expressed from the embryos of maize, Zea mays (Gramineae). It is a clear light to golden yellow oil with a faint characteristic odour and taste. Wt per ml. 0�916 to 0-923 g.

Slightly soluble in alcohol; miscible with benzene, chloroform, ether, and light petroleum. It is sterilised by heating at 150` for 1 hour.

Uses. Maize oil has similar properties to olive oil and in Australia it is an authorised substitute for olive oil in certain B.P. and B.P.C. formulae..

Foreign Pharmacopoeias; In Belg., CIO., Cz., Dan., Egyp., Fr., Ger., Jap., Jug., Mex., Nor., Span., Swed., Swiss, and U.S.

The fixed oil expressed from the ripe fruits of Olea europoea (Oleaceae). It is a pale yellow or greenish-yellow oil with a slight but not rancid odour and a bland taste. Wt per ml. 0-910 g. to 0-913 g.

Slightly soluble in alcohol; miscible with acetone, carbon disulphide, chloroform, ether, and light petroleum. It is sterilised by heating at 150˚ for 1 hour.

Uses. Internally, olive oil is nutrient, demulcent and mildly laxative. It retards the flow of the gastric juice and is employed for this purpose in gastric and duodenal ulcer in doses of to 1 fl. oz. thrice daily with meals. As a laxative, 4 to 3 fl. oz. are taken daily. It may also be given by rectal injection (5 to 20 fl. oz. warmed to about 90`F) in chronic constipation and to soften impacted faeces. Chronic colitis has been treated by retention enemas of 8 to 10 fl. oz. of the warm oil, continued nightly for a fortnight.

Externally, olive oil is emollient and soothing to inflamed surfaces, and is employed to soften the skin and crusts in eczema and psoriasis, and as a lubricant for massage. It has also been employed as a protective to burns, but its use in this manner is condemned, since it facilitates bacterial growth.

Olive oil is used in the preparation of liniments, ointments, plasters, and soaps; it is also used as a vehicle for the rectal administration of ether and paraldehyde and for oily suspensions for injection.

In preparing emulsions of olive oil of low acid value with lime water for external use, a few drops of oleic acid may be necessary in order to produce sufficient calcium oleate to act as an emulsifying agent.

Emuls. Ol. Oliv. (B.P.C. 1934) Emulsion of Olive Oil. Olive oil 10 ml., acacia 12 .5 g., tragacanth 690 mg., elixir of saccharin 0.21 ml., tincture of benzoin 1.04 ml., chloroform 0.21 ml., volatile bitter almond oil 0.1 ml., water to 100 ml. Dose: 5 to 30 mil. (0.5 to I fl. oz.)

Oleum Olivae Neutralisatum et Sterilisatum (Chil. P., Fr. P., Jug. P., Span. P., Swiss P.). Olive oil warmed with a sufficient quantity of sodium carbonate to neutralise it, then dried, filtered, and sterilised. It is used in the preparation of oily solutions for injection.

Olive Oil Enemas. (1) Olive oil, undiluted; dose: 150 to 600 ml. (5 to 20 8. oz.). (2) Olive oil 20%, v/v in mucilage of starch; dose: 600 ml. (20 fl. oz.).

Foreign Pharmacopoeias; In Chil., Chin., Fr., Ger., Jap., and U.S.

The fixed oil expressed from the kernels of varieties of Prunus persica (peach) or P. armeniaca (apricot) (Rosaceae). It is a clear, colourless or pale yellow, almost odourless oil with a bland taste. Wt per ml. about 0�92 g. Slightly soluble in alcohol; miscible with benzene, chloroform, ether, and light petroleum.

Uses. Persic oil closely resembles almond oil in its general characters and it may be used for similar purposes.

The fixed oil expressed from the seeds of varieties of the opium poppy, Papaver somniferum (Papaveracea:). It is a pale yellow odourless oil with a faint almond flavour. 'When spread in a thin film and exposed to air it forms a hard transparent varnish. 0.91g per ml.

Soluble in benzene, carbon disulphide, chloroform, ether, and light petroleum.

Uses. Poppy-seed oil is used as a substitute for olive oil for culinary and pharmaceutical purposes. It is also used in the preparation of Injection of Iodised Oil. Commercial grades are used in the manufacture of soaps, paints, and varnishes.

Foreign Pharmacopoeias: In Ca., Dan., Ger., Jap., Nor., Pal., and Swed.

The fixed oil expressed from the seeds of Brassica napus var. oleifera and certain other species of Brassica (Cruciferae). It is a pale yellow somewhat viscous oil with a characteristic odour and a taste which is unpleasant except in the most highly refined varieties. Wt per ml. 0�907 to 0�912 g. Soluble in carbon disulphide, chloroform, and ether.

Uses. Rape oil is sometimes used in liniments in place of olive oil and maybe used to replace arachis oil in Liniment of Methyl Salicylate. It is used in some countries as an edible oil.

Ravison Oil is prepared from the seeds of a wild variety of Brassica campestrip from the Black Sea region. It resembles rape oil but differs in physical constants.

Foreign Pharmacopoeias: In Chin., Ger., Hung., Ind., Jap., Mex., Swed., Swiss, and U.S.

The fixed oil expressed from the seeds of Sesamum indicum (Pedaliaceae). It is a pale yellow oil with a slight pleasant odour and a bland taste. It does not solidify when cooled to 0˚. Wt per ml. 0�91G to 0�919 g.

Slightly soluble in alcohol; miscible with carbon disulphide, chloroform, ether, and light petroleum. It is sterilised by heating at 150˚ for 1 hour. It is more stable than most other fixed oils.

Uses. Sesame oil has similar properties to olive oil and has been used instead of the latter in the preparation of liniments, plasters, ointments, and soaps.

Foreign Pharmacopoeias; In Chin., Jap., and Swed.

The fixed oil expressed from the seeds of the soya plant, Glycine soja (Leguminosae). It is a pale yellow to yellowish-brown oil with a faint characteristic odour and a bland taste. Wt per ml. about 0�92 g.

Slightly soluble in alcohol; miscible with chloroform, ether, and light petroleum. It is sterilised by heating at 150˚ for 1 hour.

Uses. It is used as an edible oil, particularly in China and Japan. It is also used as a lamp oil and in the manufacture of soaps, paints, and varnishes.

Foreign Pharmacopoeias; In Cz., Hung., and Jug.

The fixed oil expressed from the fruits (achenes) of the sunflower, Helianthus annuus (Compositae). It is a clear pale yellow oil with a faint characteristic odour and taste. Wt per nil. about 0�92 g.

Slightly soluble in alcohol; miscible with chloroform and ether. It is sterilised by heating at 150˚ for 1 hour.

Uses. It is used in some European countries as a salad oil and margarine oil, and as a substitute for olive and arachis oils in pharmaceutical preparations.