Quinine, Neutral Hydrobromate of. Syn. Quinæ hydrobromas. (M. Boille.) This salt is prepared by double decomposition of bromide of barium and neutral sulphate of quinia, and is thus easily obtained pure and free from chloride, the great solubility of bromide of barium in alcohol facilitating the removal of any chloride which is insoluble.
The two salts are dissolved separately in alcohol and the solutions filtered. The neutral sulphate of quinia solution is gradually added, in slight excess, to the bromide of barium solution until a precipitate ceases to form.
The solutions, diluted with water, are distilled to recover the alcohol, afterwards filtered to separate the sulphate of quinia which has been precipitated by the water, and then concentrated sufficiently to induce rapid crystallisation. The addition of water is indispensable for the concentration and crystallisation; the hydrobromate, being soluble in alcohol of all proportions, redissolves as the alcoholic liquor is concentrated. M. Boille claims for his neutral hydrobromate of quinine its much readier solubility over the officinal sulphate, as well as its superior richness in quinine.
Quinine, Ni′trate of. Syn. Quinæ nitras, L. Prep. As the HYDROCHLORATE, substituting dilute nitric acid, or nitrate of baryta (P. Cod.), for hydrochloric acid or chloride of barium.
Quinine, Phos′phate of. Syn. Quinæ phosphas, L. As the ACETATE. Silky, needle-shaped crystals, with a pearly lustre. It has been highly recommended in intermittents, &c., associated with rickets and stomach affections.
Quinine, Salicylate of. Syn. Quinæ salicylas. This may be made by mixing an alcoholic solution of quinine with an alcoholic solution of salicylic acid to complete saturation, and afterwards allowing the alcohol slowly to evaporate.
Quinine, Sul′phates of. The salt often called ‘disulphate of quinine’ is now generally regarded as the normal sulphate, while the soluble salt, often called the ‘neutral sulphate’
is considered to be an acid salt. This change in nomenclature results from doubling the atomic weight of the alkaloid quinine:—
1. Quinine Acid, Sulphate of. (C20P24N3O2.H2SO4.7Aq.) Syn. Sulphate of quinine†, Neutral sulphate of quinine†, Soluble s. of q.; Quinæ sulphas solubilis, L. Prep. From sulphate of quinine, 1 oz., dissolved, by the aid of heat, in water, 1⁄2 pint, previously acidulated with dilute sulphuric acid, 5 fl. dr.; the solution affords crystals on cooling, and more on evaporation.
Obs. This salt possesses the advantage of being soluble in about 10 parts of water at 60° Fahr.; but it is seldom used in the crystalline form; still, as the officinal sulphate (‘disulphate’) is generally prescribed along with a small quantity of dilute sulphuric acid to render it soluble, this acid sulphate is, in fact, the compound which is commonly given. It is the ‘bisulphate,’ ‘supersulphate,’ or ‘acid sulphate of quina’ of Soubeiran and other Continental chemists.