Glycyrrhizinum Ammoniatum (U. S. P.)—Ammoniated Glycyrrhizin.
Related entry: Glycyrrhiza (U. S. P.)—Glycyrrhiza
Preparation.—"Glycyrrhiza, in No. 20 powder, five hundred grammes (500 Gm.) [1 lb. av., 1 oz., 279 grs.]; water, ammonia water, sulphuric acid, each, a sufficient quantity. Mix four hundred and seventy-five cubic centimeters (475 Cc.) [16 fl℥, 80♏] of water with twenty-five cubic centimeters (25 Cc.) [406♏] of ammonia water, and, having moistened the powder with the mixture, macerate for 24 hours. Then pack it moderately in a conical glass percolator, and gradually pour water upon it until five hundred cubic centimeters (500 Cc.) [16 fl℥, 435♏] of percolate are obtained. Add sulphuric acid slowly to the percolate, with constant stirring, so long as a precipitate is produced. Collect this on a strainer, wash it with cold water until the washings no longer have an acid reaction, redissolve it in water with the aid of ammonia water, filter, if necessary, and again add sulphuric acid so long as a precipitate is produced. Collect this, wash it, dissolve it in a sufficient quantity of ammonia water previously diluted with an equal volume of water, and spread the clear solution upon plates of glass, so that, when dry, the product may be obtained in scales"—(U. S. P.).
Description and Chemical Composition.—"Dark-brown or brownish-red scales, without odor, and having a very sweet taste. Readily soluble in water and in alcohol. The aqueous solution, when heated with potassium or sodium hydrate T. S., evolves ammoniacal vapors. If the aqueous solution be supersaturated with an acid, there will be produced a precipitate (glycyrrhizin) which, when dissolved in hot water, forms a jelly on cooling. This substance, after being washed with diluted alcohol, and dried, appears as an amorphous, yellow powder, having a strong, bitter-sweet taste, and an acid reaction. Upon incineration, ammoniated glycyrrhizin should not leave more than a trace of ash"—(U. S. P.). This product consists largely of ammonium glycyrrhizate ([NH4]C44H62NO18) and glycyramarin (C36H57NO13), a bitter glucosid, dissolving in ether-alcohol (see Glycyrrhiza). This preparation is used mainly for masking the bitterness of quinine salts. It produces with these substances, when in solution, precipitates which contain the quinine. Hence, care must be taken to shake the vial before taking a dose.