One of the Alkaloids of Cinchona Bark.
Preparation. — Several processes have been employed for the preparation of Cinchonia. One of the simplest is the following: Powdered pale bark is submitted to the action of sulphuric or muriatic acid very much diluted, and the solution thus obtained is precipitated by an excess of lime. The precipitate is collected on a filter, washed with water, and treated with boiling alcohol. The alcoholic solution is filtered while hot, and deposits the cinchonia when it cools. A further quantity is obtained by evaporation. If not perfectly white, it may be freed from color by first converting it into a sulphate with dilute sulphuric acid, then treating the solution with animal charcoal, filtering, precipitating by an alkali, and redissolving by alcohol in the manner already mentioned. It may also be obtained from the mother- waters of sulphate of quinia, by diluting them with water, precipitating with ammonia, collecting the precipitate on a filter, washing and drying it, and then dissolving it in boiling alcohol, which deposits the cinchonia in a crystalline form upon cooling. It may be still further purified by a second solution and crystallization.
History. — When pure, cinchonia is a white, crystalline substance, soluble in 2,500 parts of boiling water, almost insoluble in cold water, insoluble in chloroform, very soluble in boiling alcohol, which deposits a portion in the crystalline state upon cooling, and slightly soluble in ether and the fixed and volatile oils. Its bitter taste, at first not very obvious in consequence Of its difficult solubility, is developed after a short time by the solution of a minute portion in the saliva. Its alcoholic, ethereal, and oleaginous solutions are very bitter. Its alkaline character is very decided, as it neutralizes the strongest acids, forming with them saline compounds. Of the salts of cinchonia, the sulphate, nitrate, muriate, phosphate, and acetate are soluble in water. The neutral tartrate, oxalate, and gallate are insoluble in cold water, but may be dissolved in hot water, in alcohol, or in an excess of acid.
Heat fuses and decomposes it, disengaging ammonia. Sulphuric acid in excess, aided by heat, renders crystallizable cinchonia amorphous. Exposed to the air it slowly absorbs carbonic acid, and acquires the property of effervescing slightly with acids, but does not become decomposed. When dissolved in water in the saline state, it may be known from any other vegetable alkali, by a reddish, somewhat orange color, produced by the addition first of a solution of chlorine, and then of ammonia to the solution. Perchloride of gold precipitates it of a sulphuryellow. Cinchonia consists of 1 equivalent of nitrogen, 20 of carbon, 12 of hydrogen, and 1 of oxygen, (N C20 H12 O). When distilled with potassa it yields quinolein.
The sulphate or disulphate of cinchonia may be prepared by heating cinchonia with a little water, adding dilute sulphuric acid gradually till the alkali is dissolved, then boiling with animal charcoal previously washed with muriatic acid, filtering the solution while hot, and setting it aside to crystallize. By alternate evaporation and crystallization, the whole of the sulphate may be obtained from the solution. It is a white, very bitter salt, crystallizing in flexible, somewhat shining, four-sided, flattened prisms, terminated by an inclined face, and generally collected in fasciculi. It is soluble in fifty-four parts of water at 60° F., and in a smaller quantity of boiling water. It consists of 100 parts of cinchonia, and 13.021 of sulphuric acid.
Properties and Uses. — Pure cinchonia, the acetate and disulphate are prescribed in medicine; their properties are said to be similar to quinia; which see. Dose, from one to four grains, three times a day.