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Comparatively Speaking: Liquid, Soft and Dry Extracts vs. Tinctures
By: Anthony J. O'Lenick, Jr., Siltech LLC
Posted: November 23, 2010
In the following excerpt, Tony O'Lenick looks to Tony Dweck to explain the difference between liquid, soft and dry extracts and tinctures.
Extracts are concentrated preparations of liquid, solid or intermediate consistency, usually obtained from dried vegetable or animal matter. For some preparations, the matter to be extracted may undergo a preliminary treatment such as inactivation of enzymes, grinding or defatting. Extracts are prepared by maceration, percolation or other suitable, validated methods using ethanol or another suitable solvent. After extraction, unwanted matter is removed if necessary.
Liquid extracts may be prepared with the methods described above using only ethanol of suitable concentration, water, or by dissolving a soft or dry extract in one of these solvents. Filtering may be necessary. Regardless of the method of preparation, all liquid extracts have a comparable composition. A slight sediment may form on standing, which is acceptable as long as the composition is not changed significantly. Liquid extracts may contain suitable antimicrobial preservatives.
Soft extracts are preparations of an intermediate consistency—between liquid and dry extracts. They are obtained by partial evaporation of the solvent used for preparation. Only ethanol of suitable concentration or water is used. Soft extracts generally have a dry residue greater than 70% w/w. They may contain suitable antimicrobial preservatives.
Dry extracts are solid preparations obtained by evaporation of the solvent used for their production. Dry extracts generally have a dry residue greater than 95% w/w. Suitable inert materials may be added. Standardized dry extracts are adjusted to the defined content of constituents, using suitable inert materials or a dry extract of the vegetable or animal matter used for the preparation. Where applicable, the monograph on a dry extract prescribe a limit test for the solvent used for extraction.