This section is from the book "Materia Medica And Therapeutics: An Introduction to the National Treatment of Disease", by John Mitchell Bruce. Also available from Amazon: The pharmacology and therapeutics of the materia medica.
5. Ethereal extracts are prepared in various ways; viz. (a) By percolating with ether and evaporating the product: Extractum Filicis Liquidum. (b) By making an alcoholic extract, macerating this in ether, and evaporating: Extractum Mezerei Aethereum. (c) By washing the drug free from oil, by percolation with ether, before making an aqueous or alcoholic extract: Extractum Ergotae Liquidum.
Acetic Extract. The only extract of this kind, Extractum Colchici Aceticum, is made like a fresh extract, but acetic acid is added to the crushed corms before expression, and evaporation is arrested whilst the mass is soft.
7. Liquid extracts are prepared by macerating the drug in water, evaporating to form a concentrated solution, and adding a little spirit to prevent decomposition. Ex.: Extractum Pareirae Liquidum. The process is modified in the case of ergot and filix mas, as described under ethereal extracts.
The consistence of extracts varies much. Some are liquid; four are solid, viz. those of aloes (2), haematoxylum, and krameria; five are soft, viz. the acetic extract of colchicum, and the extracts of cannabis indica, mezereon, nux vomica, and physo-stigma; the rest are of the consistence suitable for forming pills.
Glycerina, Glycerines, are solutions of substances in glycerine. They are suitable either for further solution or for application locally,
Infusa, Infusions, are obtained by steeping vegetable substances in water, generally near the boiling point. The infusions of calumba and quassia are made with cold water; those of chiretta and cusparia with water at 120° Fahr. Those of orange and gentian are compound; that of roses contains acid.
Linimenta, Liniments, or embrocations, are preparations suitable for application by rubbing, anointing, or painting. All liniments contain either camphor, oil, or soap.
Liquores, Solutions proper, consist of substances other than volatile oils dissolved in water; but the preparations of many are complicated, solution being assisted by spirit, acids, ether, lime, other salts, or carbonic acid as in the effervescing liquores.
Lotiones, Lotions, or washes, are solutions or mixtures for external use by washing or on lint. The British Pharmacopoeia contains but two lotions, Lotio Hydrargyri Flava, and Lotio Hydrargyri Nigra.
Mellita, Honeys, are fluid preparations containing a large proportion of honey.
Misturae, Mixtures, are made by rubbing up various substances in water, the product being not a solution, but a mixture only. The insoluble substances are generally suspended in the water by means of gum, spirit, or milk. They are frequently compound.
Mucilagines, Mucilages, are solutions of colloid substances in water.
Oleum, an Oil, is a solution in a fixed oil. Ex.: Oleum Phosphoratum.
Pilulae, Pills, are soft easily divisible masses, variously composed of extracts or substances naturally tenacious, with suitable "excipients," such as treacle, confection of roses, or powdered liquorice. They are almost all complex. The substances best adapted for giving in pill form are such as are not conveniently given in fluid form, or those intended to act slowly.
Pulveres, Powders, are compounds of dry substances reduced to powder and intimately mixed.
Spiritus, Spirits, are either simple or complex. Simple spirits are solutions of colourless substances or oils in rectified spirit, the latter of the strength of 1 in 50. Ex.: Spiritus Chloroformi, Spiritus Cajuputi. Complex spirits are prepared in a special manner; e.g. Spiritus .Aetheris Nitrosi.
Succi, Juices, are the expressed juices of the fresh plants, to which one-third of their volume of spirit has been added to preserve them. Limonis Succus, Rhamni Succus, and Mori Succus, are not preparations, but natural products.
Suppositoria, Suppositories, are solid conical bodies, composed of active ingredients and various mixtures of fats and wax, or starch and soap, adapted for introduction into the rectum, where they are intended to melt.
Syrupi, Syrups, are fluid preparations containing a large amount of sugar.
Tincturae, Tinctures, are solutions in spirit, either alone or combined with other solvents. They may be grouped according to (1) the solvent, (2) the process, or (3) the ingredients.
Solvents. Rectified spirit is chiefly used when the substances contain resin or volatile oil, as in cannabis indica. Proof spirit is adapted when the substances are partly soluble in water, partly in spirit, as in most tinctures. Ammonia is employed in the ammoniated tinctures of opium, valerian, quinine, and guaiacum; spirit of ether in Tinctura Lobeliae Ętherea,; and tincture of orange in Tinctura Quiniae.
Processes. (a) Simple solution or mixture. Ex.: Tinctura Ferri Perchloridi. (b) Maceration. Macerate the drug in the spirit for seven days; press, if necessary; strain; and add sufficient spirit to make one pint. Ex.: Tinctura Opii. (c) Percolation. Pour the spirit on the drug packed in a percolator, and add spirit slowly until one pint is collected. Ex.: Tinctura Zingiberis Fortior. (d) Maceration and percolation. Macerate the drug for forty-eight hours in part of the spirit; then percolate, adding more spirit as required; press, filter the products, mix the liquids, and add spirit to one pint. Ex.: Tinctura Digitalis.
Ingredients. Tinctures are either simple, or compound, i.e. contain more than one active substance. Ex: Tinctura Benzoini Composita.
Trochisci, Lozenges, are dried tablets of sugar, gum, mucilage, water, and one or more active ingredients, uniformly divided or previously dissolved Unguenta, Ointments, are mixtures of active substances with lard, benzoated lard, suet, wax, or oil, variously combined; or with simple ointment. The ingredients are either thoroughly mixed or melted together.