This section is from the book "A Text-Book Of Pharmacology, Therapeutics And Materia Medica", by T. Lauder Brunton. Also available from Amazon: A text-book of pharmacology, therapeutics and materia medica.
These are very dry, powdered extracts. They are twice the strength of the crude drug, and about twice the strength of the corresponding fluid extracts. They are prepared by extracting the active principles from 200 parts of the crude drug by percolation with the strong or diluted alcohol, mixing the percolate with some sugar of milk, letting it dry, and then adding sufficient sugar of milk to make up the product to 100 parts. They are eleven in number.
1/2 - 1 1/2gr.
3-4 fluid dr.
Alkaloidea. Alkaloids. - These are organic bases which may be regarded as compound ammonias.
Like ammonia they all contain nitrogen, and form salts with acids. Most of them contain oxygen in addition to nitrogen, carbon, and hydrogen, and occur as crystalline solids. Some, e.g. coniine, nicotine, sparteine,piperidin, contain no oxygen, and occur as oily liquids. They generally have a powerful physiological action. They occur in many exogenous plants, but only veratrine and substances nearly allied to it have been obtained from the class of endogens and muscarine from thallogens. They occur in the plants in combination with acids. The alkaloids themselves are generally soluble in alcohol, but sparingly soluble in water. Their salts are more soluble in water. The general plan of obtaining them is to prepare an aqueous solution either of the salt originally present in the plant, or of one formed by treatment with an acid, and to precipitate them by an alkali, generally ammonia, from it. As the alkaloids are soluble in alcohol they would be very imperfectly precipitated, or not at all, if the ammonia were added to an alcoholic solution of their salts.
In the B.P. of 1867 the names of alkaloids all terminated in 'ia,' like ammonia, e.g. quinia, strychnia. Chemists have now generally returned to the older nomenclature, and assign the termination 'ine' to alkaloids, e.g. strychnine, quinine. To neutral principles they give the termination 'in,' e.g. santonin, salicin. This terminology has been followed in the B.P. of 1885 and the U.S.P. of 1883.
General Properties and Reactions of Alkaloids. - Alkaloids are basic in nature, like ammonia, forming salts with acid radicals, easily decomposed by the action of alkalies and alkaline carbonates.
Alkaloids are, for the most part, insoluble in water, with the exception of brucine and codeine, which are readily soluble; they are all soluble in alcohol, benzene, and chloroform. Their salts are soluble in water, and have the property of turning the plane of polarised light to the left: cinchonine, conchinine, coniine, laudanosine, however, turn the plane to the right. Some alkaloids have no effect on polarised light, e.g. berberine, crypto-pine, emetine, hydrocotarnine, narceine, veratrine, caffeine, and piperine.
In solution, alkaloids are precipitated by a solution of iodine in iodide of potassium, by potassio-mercuric iodide, and a similar double iodide of cadmium and bismuth, also by picric acid and by phospho-molybdic and phospho-tungstic acids.
Aconitina (Aconitine). Apomorphinae Hydrochloras (Hydro-chlorate of Apomorphine). Atropina (Atropine). Atropinae Sulphas. Beberinas Sulphas (Sulphate of Beberine). Caffeina (Caffeine). Caffeines Citras (Citrate of Caffeine). Cinchonidinae Sulphas (Sulphate of
Morphinae Acetas (Acetate of Morphine). ,, Bimeconatis Liquor (Solution of Bimeconate of Morphine). ,, Hydrochloras (Hydrochlorate of Morphine). ,, Sulphas (Sulphate of Morphine). Physostigmina (Physostigmine). Pilocarpinae Nitras (Nitrate of Pilocarpine). Quininae Hydrochloras (Hydrochlorate of Quinine). 'Quininae Sulphas (Sulphate of Quinine). Strychnina (Strychnine). Strychninae Hydrochloras (Hydrochlorate of Strychnine). Veratrina (Veratrine).
Apomorphina (Apomorphine). Atropina (Atropine). Atropinae Sulphas (Sulphate of Atropine). Caffeina (Caffeine).
Cinchonidinae Sulphas (Sulphate of Cinchonidine). Cinchonina (Cinchonine). Cinchoninae Sulphas (Sulphate of Cinchonine). Codeina (Codeine). Hyoscyaminae Sulphas (Sulphas of Hyoscyamine). Morphina (Morphine). Morphinae Acetas (Acetate of Morphine). Morphinae Hydrochloras (Hydrochlorate of Morphine). ,, Sulphas (Sulphate of Morphine). Physostigminae Salicylas (Salicylate of
Quinine). Quininae Hydrobromas (Hydrobromate of Quinine). „ Hydrochloras (Hydrochlorate of Quinine). „ Sulphas (Sulphate of Quinine).
Quiniae Valerianas (Valerianate of Quinine). Strychnina (Strychnine). Strychninae Sulphas (Sulphate of
Strychnine). Veratrina (Veratrine).
Chinoidinum (Chinoidin or Quinoidin), U.S.P., is a mixture of bases.
Along with the alkaloids may be mentioned several neutral principles which resemble alkaloids in having a powerful physiological action.
Chrysarobinum (Chrysarobin). Picrotoxinum (Picrotoxin). Salicinum (Salicin). Santoninum (Santonin).
The substances whose names are printed in italics in the above list are not pure principles. The chrysarobinum of the pharmacopoeias is a mixture of substances containing chrysarobin and chrysophanic acid, and ergotin is only a purified extract of ergot. Lupulinum (B.P.) is only a glandular powder derived from hops, although from the sound of its name it might be supposed to be an active principle.