The author believes the decomposition of hydrochlorate of ammonia by an organic alkali to have been hitherto unobserved. It does not appear, however, that emetine is alone in this action, as the author has observed that quinine, under similar conditions, behaves in the same manner.
Zinoffsky (‘Jour. de Pharm. d’Anvers,’ xxix, 490) gives the following process for the quantitative determination of emetia:—Treat fifteen grams of powdered ipecacuanha with alcohol of 85 per cent., acidified with a few drops of sulphuric acid, so as to form a volume of 150 cubic centimètres. Filter, and after expelling the alcohol from 100 cubic centimètres of the liquid by distillation, add to the residue a titrated solution of iodo-hydrargyrate of potassium until a filtered portion ceases to be affected by this reagent. The number of cubic centimètres of iodo-hydrargyrate multiplied by 0·0189 (0·0001 of the equivalent of emetine) gives the quantity of emetine contained in ten grains of the root.
A normal solution of iodo-hydrargyrate is obtained by mixing aqueous solutions of 13·546 grams of bichloride of mercury, and 49·8 of iodide of potassium, adding water to make one litre. One cubic centimètre of this solution precipitates 0·0001, or 0·00005 of an equivalent of alkaloid.
Wine of ipecacuanha can be titrated by the same process.
Composition of Emetine and its Hydrochlorate.—These substances dried at 110° C., gave upon analysis results corresponding with following centesimal composition:
| Emetine. | Hydrochlorate of Emetine. | |
| Carbon | 72·25 | 63·00 |
| Hydrogen | 8·61 | 8·15 |
| Nitrogen | 5·36 | 4·75 |
| Oxygen | 13·78 | 11·64 |
| Chlorine | 12·46 |
From these figures the author has constructed the following formulæ:
Emetine: C30H22NO4. Hydrochlorate of Emetine: C30H22NO4HCl.
Preparation and Composition of Emetine (J. Lefort and F. Wurtz, ‘Comptes Rendus,’ lxxxiv, 1299). When ipecacuanha is dissolved in water, and a concentrated solution of potassium nitrate added, a thick mass is produced, consisting of emetine nitrate. It is washed with water, dissolved in alcohol, and the solution poured into milk of lime. The mixture is evaporated to dryness, and digested with ether, which dissolves out the emetine, leaving it as a yellowish mass on evaporation. On dissolving this mass in sulphuric acid, and pouring the solution into dilute ammonia, the alkaloid is obtained as a white precipitate, which is dissolved in alcohol, from which it separates in minute radiate groups of needles. By analysis it gave numbers leading to the formula C28H40N2O3.[275]
[275] Note by the translator (‘Journal of Chem. Soc,’): “This is printed C28N2H40O5 in the formula for emetine nitrate, and as no data are given, it is impossible to tell which are correct.”