Medicated Waters.
BY JOSEPH W. ENGLAND, PH. G.
Read at the Pharmaceutical Meeting, January 15, 1884.
The term "Medicated Waters" is applied in a general sense to all those aqueous liquids holding in solution the volatile oils of plants, or in some cases the stearopten of a volatile oil e. g. Aqua camphorae. This definition is only partially adhered to by the Pharmacopoeia which also admits under the same heading, aqueous solutions of certain odorous gases and liquids not directly derived from plant life. Through misplacement, therefore, Aqua ammoniae, Aqua ammoniae fortior, Aqua chlori and Aqua creasoti have been classified among the officinal waters, the position of which, it is thought, from their composition should have been among the "Liquors." The present paper will deal only with the waters first named; that is those derived from volatile oils; and will have for its scope the various methods of preparations employed, explanations of the several advantages and disadvantages peculiar to each; while a substitutive process will be offered and the principles involved in the workings of the same set forth.
The U. S. Pharmacopoeia of 1870, in the formulae for these waters, gave in all cases, either one or the alternative of two processes. First: Distillation of the odorous part of the plant with water, after previous comminution and maceration if necessary; or, second: Trituration of the volatile oil of the plant with magnesium carbornate, the addition of distilled water and filtration.
During the process of "distillation" the water carries over with it in suspension the vapor of the oily product used and both are condensed in the receiver in separate layers. The oily portion is separated by suitable apparatus, leaving the water impregnated with its taste and fragrance. The fragrance is at first masked with a foreign odor that gradually disappears on exposure to air; leaving the true one, partially modified to one of finer quality, through the supposed presence of certain volatile acids and compound or mixed ethers. Distillation while admittedly the best in comparison with the present methods pursued, is to a great extent in the limited uses of most pharmacists impracticable for general employment. It requires for its successful exercise, the manufacture on a large scale, great care and skill on the part of its operators, and the use of vegetable products of quality seldom found in commerce to secure the best results. Its general application, therefore, is far from being a universal one.
The process of triturating the oil with magnesium carbonate is directed for the property possessed of reducing, mechanically, the size of the oily globules in order to present a greater surface to the solvent action of the water. The main objection to its use, rests upon the fact of its appreciable solubility in distilled water and to a still greater extent, when ordinary water containing in solution, as it usually does, carbonic oxide. The medicated waters thus made and holding in solution this alkaline-earth salt may, when prescribed with alkaloids, their salts or certain metallic oxides, precipitate them from solution on standing and possibly lead to grave and serious results. To overcome this defect the substitution of paper-pulp, chalk, pumice stone or charcoal has been proposed. These, however, are poor expedients and all fail through their inherent lack of the necessary power of diffusion of the oily ingredient upon trituration. The advantages of the "Trituration Process" to the general pharmacist are so manifold that they scarcely need comment. The readiness of manufacture on a small scale, the short time necessary for its performance with results equally satisfactory, except in a few isolated instances, and the cheapness of preparation are a few of the points of value which yield it preference for general usage.
The late revision of our recognized authority discards, entirely, the use of the "Trituration Process" and employs in its stead a method which consists, simply, in the distribution of the oil, in small portions at a time, upon cotton; picking the same apart after each addition until the whole is thoroughly impregnated with it, packing in a conical glass percolator and displacing with distilled water. The exceptions to this mode are bitter almond water, prepared by direct solution of the oil in water by agitation, rose and orange flower waters made by distillation. A practical acquaintance with this process does not impress one with either its worth or general utility. Its supposed advantages are more than counterbalanced by the very unsatisfactory results arising from its use. In the first place when the oil is added to the cotton, no matter how faithfully its dissemination may be executed, a large proportion is necessarily lost upon the fingers in picking the fibres apart. Then when it is placed in the percolator, if packed too loose, the added water rushes through without dissolving any of the oil. If too tight: the process is impeded to such an extent that percolation becomes impossible. The right degree of packing is hard to obtain and when secured yields but little better results. As to the use of distilled water, very few follow the pharmacopoeial directions in this particular. Without exceptions, all pharmacists with whom the author has conversed, substitute ordinary water and claim in extenuation, that extreme purity of that liquid is unnecessary, and that they are perfectly justified in the replacement from the fact that distilled water is frequently of a musty, unpleasant odor, vapid and disagreeable taste and as likely may contain metallic impurities from the uncertain, careless methods of commercial manufacture; further their efficiency is called into question from the physiological fact that distilled water is difficult of digestion and not as acceptable to irritable stomachs. These statements may be regarded as extreme, yet it must be admitted that the greatest efficiency of all medicines is desired, in a physiological sense as well as a pharmaceutical one. If the reasons advanced are tenable and do not arise from economic considerations they are certainly worthy of further notice. Certain it is that the products made by them, seem to give equal satisfaction with those made by standard authority. In whatever way we view the U. S. (1880) process, its wasteful and objectionable manipulations are so evident, that if the imperfections in the directions of the earlier Pharmacopoeia (1870) were open to severe comment, those of the latter (1880) are doubly so by comparison.
As previously stated, the greater the subdivision of an oil, when brought in contact with an aqueous solvent, the larger the quantity that will necessarily be taken up in solution. As an aid to this fact and also their supposed insolubility, rests the adaptability of the bodies mentioned above as diffusive agents. Some of the objections to the use of magnesium carbonate and several of its proposed substitutes have already been noted. Upon trial I have found precipitated calcium carbonate to be preferable, mechanically, to the magnesium salt; yet it is open to the same adverse criticisms. Another possibly important objection to the use of alkaline earth carbonates, which has not been previously discussed, may reside in the fact of the presence of odorous volatile acids, ethers, etc., in the volatile oils used and the neutralization of those acids by the alkaline carbonates, to form neutral and inodorous bodies, which may or may not be soluble. This view is a plausible one when we consider the delicate chemical constitution of the oils in general, especially those containing the previously mentioned compounds. Upon this fact may be based the superiority of "Distilled" over "Triturated" waters, as in distillation the water is impregnated with the oil direct and unchanged; while in trituration, if performed with carbonates, some changes undoubtedly ensue, since the products from the latter process are of less fine qualities than those of the former; although both may be made from the same oil. It is absolutely necessary on this account, to use a body free from these objectionable features and one which has all the essential requisites in the greatest degree. After numerous trials I have found precipitated calcium phosphate to possess all the desired properties and to yield products that were in all respects the equal of those obtained by distillation.
This lime salt is a neutral, impalpable solid, wholly insoluble in water, neutral or carbonated, and when used permits nitration much more readily and effectively than any other medium. In diffusive power it is fully the equal of any of the bodies previously mentioned; leaving nothing to be desired. Before its use, although generally very pure, tests should be always applied to determine that fact. It should be wholly soluble in dilute hydrochloric acid without effervescence (absence of carbonates). Its washings with distilled water should yield no opalescence or precipitate with test solutions of silver nitrate (absence of chlorides), barium chloride (absence of sulphates) or ammonium oxalate (absence of soluble lime salts).
When diffusive agents are used, they require long and persistent trituration with the oil to effect thorough and minute subdivision. In order to promote this diffusion, a plan of diluting the oil with a small quantity of alcohol was tried and found to work admirably. The presumed presence of alcohol in medicated waters thus made, has no foundation in fact, if the directions in the general formula, hereinafter given, are followed, as the rubbing to dryness, necessarily volatilizes the whole of it.
General Formula.—"Triturate, in a mortar of broad surface, the oil dissolved in the alcohol, with the precipitated calcium phosphate, until a dry powder is secured and all the alcohol has volatilized, then add the water in small portions at a time, stirring after each addition, until the intended quantity to be made is completed. Lastly, filter; returning to the filter the first portions, if cloudy."
The following formulae, under each heading, are expressed in two ways. One according to the method of the U. S. P. of 1870, and the other like that of the U. S. P. of 1880.
Aqua Anethi, Br.—Oil of dill half a fluidrachm, alcohol one and a half fluidrachms, precipitated calcium phosphate two drachms, distilled water a sufficient quantity to make the finished product measure two pints. Or, oil of dill 2 parts, alcohol 6 parts, precipitated calcium phosphate 8 parts, distilled water a sufficient quantity to make the finished product weigh 1,000 parts.
Aqua Anisi, U. S.—Oil of anise half a fluidrachm, alcohol one and a half fluidrachms, precipitated calcium phosphate two drachms, distilled water a sufficient quantity to make the finished product measure two pints. Or, oil of anise 2 parts, alcohol 6 parts, precipitated calcium phosphate 8 parts, distilled water a sufficient quantity to make the finished product weigh 1,000 parts.
Aqua Aurantii Florum, U. S.—Oil of neroli (Bigarade) twelve minims, alcohol one and a half fluidrachms, precipitated calcium phosphate two drachms, distilled water a sufficient quantity to make the finished product measure two pints. Or, oil of neroli (Bigarade) 2 parts, alcohol 15 parts, precipitated calcium phosphate 20 parts, distilled water a sufficient quantity to make the finished product weigh 2,500 parts.
Aqua Amygdalae Amarae, U. S.—Oil of bitter almonds 15 minims, distilled water a sufficient quantity to make the finished product measure two pints. Or, oil of bitter almonds 1 part, distilled water a sufficient quantity to make the finished product weigh 1,000 parts. Dissolve the oil directly in the water by agitation. Since 1 part of the oil is soluble in 300 parts of water, no further directions are necessary.
Aqua Camphorae, U. S.—Camphor two drachms, alcohol one and a half fluidrachms, precipitated calcium phosphate four drachms, distilled water a sufficient quantity to make the finished product measure two pints. Or, camphor 8 parts, alcohol 6 parts, precipitated calcium phosphate 15 parts, distilled water a sufficient quantity to make the finished product weigh 1,000 parts. Reduce the camphor in a mortar to a thin, smooth paste with the alcohol, add the precipitated calcium phosphate, and proceed as in general formula.
Aqua Cinnamomi, U. S.—Oil of cinnamon (Ceylon) half a fluidrachm, alcohol one and a half fluidrachms, precipitated calcium phosphate two drachms, distilled water a sufficient quantity to make the finished product measure two pints. Or, oil of cinnamon (Ceylon) 2 parts, alcohol 6 parts, precipitated calcium phosphate 8 parts, distilled water a sufficient quantity to make the finished product weigh 1,000 parts.
Aqua, Foeniculi, U. S.—Oil of fennel half a fluidrachm, alcohol one and a half fluidrachms, precipitated calcium phosphate two drachms, distilled water a sufficient quantity to make the finished product measure two pints. Or, oil of fennel 2 parts, alcohol 6 parts, precipitated calcium phosphate 8 parts, distilled water a sufficient quantity to make the finished product weigh 1,000 parts.
Aqua Menthae Piperitae, U. S.—Oil of peppermint half a fluidrachm, alcohol one and a half fluidrachms, precipitated calcium phosphate two drachms, distilled water a sufficient quantity to make the finished product measure two pints. Or, oil of peppermint 2 parts, alcohol 6 parts, precipitated calcium phosphate 8 parts, distilled water a sufficient quantity to make the finished product weigh 1,000 parts.
Aqua Menthae Viridis, U. S.—Oil of Spearmint half a fluidrachm, alcohol one and a half fluidrachms, precipitated calcium phosphate two drachms, distilled water a sufficient quantity to make the finished product measure two pints. Or, oil of spearmint 2 parts, alcohol 6 parts, precipitated calcium phosphate 8 parts, distilled water a sufficient quantity to make the finished product weigh 1,000 parts.
Aqua Pimentae, Br.—Oil of allspice half a fluidrachm, alcohol one and a half fluidrachms, precipitated calcium phosphate two drachms, distilled water a sufficient quantity to make the finished product measure two pints. Or, oil of allspice 2 parts, alcohol 6 parts, precipitated calcium phosphate 8 parts, distilled water a sufficient quantity to make the finished product weigh 1,000 parts.
Aqua Rosae, U. S.—Oil of rose six minims, alcohol one fluidrachm, precipitated calcium phosphate two drachms, distilled water a sufficient quantity to make the finished product measure two pints. Or, oil of rose 2 parts, alcohol thirty parts, precipitated calcium phosphate 40 parts, distilled water a sufficient quantity to make the finished product, weigh 5,000 parts.
In conclusion, the author, in advocating the adoption of the preceding formulae would say that any means used to insure success, are always secondary in importance to the quality of the materials used. No process, however good in itself, can hope to remedy defects in the qualities of its ingredients, or the hasty, careless manipulations of its operators. With these guarded against, there need be no disappointment in the results obtained.
The American Journal of Pharmacy, Vol. 56, 1884, was edited by John M. Maisch.
