This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
The United States Pharmacopeia of 1890 directed that aconite be made in tincture representing 35 per cent drug strength, veratrum 40, lobelia and hydrastis 20, and most of the other potent drugs 15 per cent. But by international consent most tinctures are now of an uniform 10 per cent strength. There are arguments favorable to this procedure; but, as a practical matter of fact the number of official tinctures shows a decline. A 10 per cent tincture of aconite may be entirely satisfactory, but not so with calumba, cardamon, cimicifuga, cinchona, gambir compound, gentian compound, guaiac, hydrastis, kino, krameria, musk, rhubarb, and valerian, the average dose of each one of which is given as one fluidrachm, in the United States Pharmacopeia, VIII, while the average dose of camphorated tincture of opium is two fluidrachms. This involves the administration of too much alcohol, the products are too bulky to be convenient to dispensing physicians, and the price is necessarily high.
The alcohol problem must be sincerely met. I have known physicians to give the Homeopathic mother tincture of passiflora in two teaspoonful doses for the relief of insomnia due to painful affections, in which form of insomnia passiflora is of no value, and they would push these doses at frequent intervals, never realizing that it was the alcohol that made these patients sleep.
Valerian is a useful drug, but giving quantities of alcohol with it negatives its finest action. Suppose you wish to give cimicifuga to a patient suffering from chorea, would you wish also to administer quantities of alcohol along with it? Certainly not, as it would be irrational to do so; yet that is precisely what one does in using the United States Pharmacopeia tincture of the eighth revision, now transferred to the National Formulary.
On the other hand, grain alcohol in proper strength - aided occasionally by other solvents - is the one agent which extracts from a plant its active medicinal content and at the same time does not dissolve the starch, albumen, pectin, and other inert ingredients. In proper concentration, it is possible to make an alcoholic tincture each minim of which represents one grain of the drug, at least as regards the larger number of botanic drugs. It is not contended that a drug worked green, like cactus, can be so concentrated in tincture form; nor is it held that such concentrated agents can be uniformly made in a drug store percolator. But, with proper machinery, the large makers of tinctures and extracts may readily do so with most botanic agents.
2 See further notes under "Improving Conditions" near the close of this section.
The content of absolute alcohol in such concentrated tinctures will range, approximately, from 50 to 90 per cent. The commercial and scientific possibilities of such concentrated products are testified to by the fact that for many years several lines of them have been upon the market.
Normals were introduced to meet the general demand for a fluid preparation of definite composition - to meet the needs of all branches of the profession employing them similarly to the fluid-extracts, and in place of the latter where lack of confidence in the average commercial fluidextract has resulted from the use of dried and otherwise inferior drugs in their manufacture, especially of plant remedies that break down under ordinary gathering, curing, and extraction.
In most of them 480 grains of the drug is represented in one fluidounce of the finished product; but, in the normals, an improvement over the earlier green plant preparations has been accomplished in the standardization of the drug to a uniform relation of the dry drug to the finished tincture, thus securing uniformity of dosage and, at the same time, a greater strength and reduced dosage as compared with the earlier green plant unstandardized products.
In "Specific Medicines," another one of these lines, certain disturbing agents, or agents so regarded, are eliminated from a number of the products. This applies more especially to "Sp. Med. Digitalis" and "Sp. Med. Hydrastis." They were devised to meet the requirements of Eclectic physicians, but their use has spread to other physicians.
As a class, these products are very satisfactory, precipitate but little, are well made from the pharmaceutical standpoint, and are exceedingly active pharmacologically. This list includes many botanic drugs not commonly available in the form of fluid-extracts.
But, like in the making of fluidextracts, to produce such concentrated tinctures so they will assay up to alkaloidal standard, and yet not precipitate in time, requires elaborate processes in manufacture.
In order to avoid these troubles and make the fabrication of such concentrated products within the reach of the retail pharmacist, the Journal of North American Retail Druggists suggested the abolition of our present tinctures and fluidextracts and the substitution of an uniform 50 per cent tincture; and these are the reasons given: Fluid-extracts are difficult to make without elaborate apparatus using heat, thus making the product of poor quality and causing many drugs to fall into disrepute from failing in the hands of physicians. Official tinctures contain too much alcohol for the good of the patient when adequate doses are given. Because of unsatisfactory conditions in the preparation of products of botanic drugs, proprietary specialties of actual efficiency are taking the place of official preparations. With 50 per cent tinctures, opportunity would exist to flavor and sweeten drugs prescribed in admixture and still maintain the dose as one teaspoonful.
From the standpoint of retail pharmacy, these are admirable recommendations; but from the point of view of the physician, the points raised testify to the fact that he is obliged to specify when he prescribes fluidextracts, for many of them are simply concentrated decoctions or weak alcoholic extracts made in vacuum pans and with just sufficient alcohol added to prevent fermentation but not precipitation.3
Of course, there are careful manufacturers who are making good fluidextracts, assayed and physiologically standardized wherever possible; and these makers are quite inclined to make products guaranteed to be of United States Pharmacopeia standard but not always made by United States Pharmacopeia processes.
It is cheaper to extract a drug quickly in a heated vacuum pan than by slow percolation and re-percolation, using a sufficient percentage of alcohol. Cheap fluidextracts are the real basis for a lot of therapeutic nihilism. But United States Pharmacopeia processes are improving, from revision to revision, and fluidextracts are being better made than they were a few years ago, at least by representative houses.
Physicians care little for the nomenclature of finished drug extracts, and they are not at all interested in maintaining processes simply because they serve the purposes of the retail pharmacist. We want our tinctures and extracts of botanic drugs to be thoroughly representative; and this requires the use of a highly alcoholic menstruum, extraction with the minimum of heat or none at all, the use of good crudes in proper condition, the proper employment of assay and physiologic standardization processes, and careful storage and packing of honestly labeled products.
United States Pharmacopeia extracts are, of course, reduced by the application of some heat. Properly made, they are satisfactory products, the plants of more fragile structure being seldom made up into extracts. There are powdered, soft and solid extracts.