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.
Reference has been made to successive pharma-copeial revisions improving conditions.
There is before me as I write this section (1916) advanced proof from the Ninth United States Pharmacopeia revision. Fluidextracts are directed to be made according to type processes; process A is by percolation with a menstruum of alcohol or alcohol and water; process B uses glycerin or an acid in extraction and two menstrua (alcohol the second) are successively used; process C is that of fractional percolation, and process D employs boiling water, alcohol being added to the concentrated extract as a preservative. A is used in 29 official fluidextracts, B in 10, C in 3, and D only in extracting cascara and triticum. Licorice and senega are extracted by special processes. Temperature must never exceed 140° F. in process A and only to a portion of the filtrate; process B the same; process C no heat; process C uses boiling water, but the temperature is not continued higher than the water-bath runs. Nearly all of these fluidextracts are strongly alcoholic.
Tinctures are not appreciably improved in the Ninth Revision except that veratrum viride is alone recognized, veratrum album being dropped. There are, as regards a few drugs, some improvements in detail. Powdered and pilular extracts are made by much improved processes.
Wherever assay processes are defined, they are recognized. The 49 United States Pharmacopeia fluidextracts, Ninth Revision, are to be commended as an advance over previous products; but many will be used that are nonofficial; and in purchasing these latter physicians should exercise much discrimination. There are 90 fluidextracts in the new National Formulary, and these are made by processes similar to those of the United States Pharmacopeia, IX.
Homeopathic mother tinctures are mostly 10 per cent drug strength in concentrated alcohol, many being prepared from the green or recent drug. "German tinctures," a trade name, not an official one, are very similar to the Homeopathic mother tinctures.