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Alcohol. Alcohol.

Preparations:

Related entries: Spirits

C2H6O = 46.048.
Synonym.—Ethyl Alcohol.

Spiritus Rectificatus, B.P., alcohol (90 per cent.), is obtained by the distillation of fermented saccharine liquids, and contains 90 per cent. by volume of ethyl hydroxide, C2H5OH. Alcohol should be kept in well-stoppered vessels in a cool place, remote from lights or fire. Alcohol occurs as a transparent, colourless, mobile, volatile liquid, with a slight agreeable odour, and a strong burning taste. It consists of 85.65 per cent. by weight of ethyl hydroxide, and 14.35 per cent. by weight of water. Specific gravity, 0.834. Alcohol, U.S.P., contains 94.9 per cent. by volume of ethyl hydroxide, and its specific gravity is about 0.816 (or 0.809 at 25°). Alcohol Dilutum, U.S.P., is prepared by mixing equal volumes of alcohol (94.9 per cent.) and distilled water; it contains 48.9 per cent. by volume of ethyl hydroxide, and its specific gravity is about 0.936 (or about 0.930 at 25°).

Miscible in all proportions with water, ether, or chloroform.

Diluted alcohol of different strengths may be prepared by mixing alcohol and distilled water in the proportions stated in the following formulae, the volumes of alcohol and water specified in each case being sufficient to produce 100 volumes of the required mixture at 15.5°:—

1. Alcohol (70 per cent.)
Alcohol 77.77
Distilled Water 24.16
Mix. The specific gravity of the resulting liquid is 0.8900
2. Alcohol (60 per cent.)
Alcohol 66.66
Distilled Water 35.78
Mix. The specific gravity of the resulting liquid is 0.9135.
3. Alcohol (45 per cent.)
Alcohol 50.00
Distilled Water 52.66
Mix. The specific gravity of the resulting liquid is 0.9436.
4. Alcohol (20 per cent.)
Alcohol 22.22
Distilled Water 79.10
Mix. The specific gravity of the resulting liquid is 0.9760.

Alcohol (95 per cent.) can be prepared extemporaneously by mixing equal volumes of alcohol (90 per cent.) and absolute alcohol. Proof spirit (Spiritus Tenuior, s.g., 0.920) contains 49.24 per cent. of ethyl hydroxide, and spirits are described as so many degrees over or under proof (o.p. or u.p.), according to the quantity of distilled water which must be added to or deducted from 100 volumes, in order to produce spirit of proof strength. Alcohol (90 per cent.) corresponds very nearly to 58 over proof, and 100 volumes thus contain almost as much real alcohol as 158 volumes of proof spirit. Methylated spirit is a mixture of 19 parts of alcohol of a strength of not less than 50 over proof (about 86 per cent. alcohol) and 1 part of commercial wood naphtha. This "Industrial Methylated Spirit" is supplied free of duty for manufacturing purposes only. For retail sale, "Mineralised Methylated Spirit" is supplied to licensed retailers, and consists of a mixture of 9 parts of alcohol and 1 part of wood naphtha, with the addition of not less than 3/8 per cent. of petroleum oil or mineral naphtha, of specific gravity not lower than 0.800.

Action and Uses.—Diluted alcohol is used externally as an evaporating lotion in various forms of skin-inflammation; it is also employed to diminish sweating. Alcohol hardens the skin by dehydration, and is therefore employed to harden the nipples before lactation, and to prevent bedsores; it is also used in surgery to sterilise the skin of the patient and the hands of the operator. Internally it may be useful as a mild gastric stimulant and carminative; unquestionably it accelerates absorption, and may be administered with other drugs for this purpose. It depresses the central nervous system, and benefits which are obtained from its use in the various conditions known as nervous shock—conditions in which the brain may be already over-excited—are due to its depressant action and not, as has been said, to a stimulant effect. It has also been employed, especially in old age, as a mild hypnotic. As a circulatory stimulant the value of alcohol is undoubted; it increases the output of blood from the heart, and slightly raises blood pressure. It should be remembered, however, that it dilates the skin-vessels, and its use should therefore be avoided in those exposed to cold. Its action may be due either to a direct stimulant effect on cardiac muscle, or to the fact that it affords a readily assimilable source of energy. The most important action of alcohol is on metabolism; in ordinary doses it is almost completely oxidised, and spares the oxidation of fat. Moreover, in those moderately addicted to its use, it can, like fats and carbohydrates, replace a certain quantity of protein; and it surpasses starch and sugar in alimentary value, since weight for weight it contains more energy. In excessive amounts it has a toxic action. It is employed as a food both during fevers and in convalescence from fevers, but when used for this purpose the dose should not exceed 3 or 4 fluid ounces of alcohol per diem. Hypodermic injections of alcohol over the affected nerve have proved of service in intractable neuralgias.

PREPARATION.

Lotio Evaporans, B.P.C.—EVAPORATING LOTION. 1 in 5.
Used as a cooling dressing for sprains and bruises. It is sometimes prepared with methylated spirit.

The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.



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