EMETIA

Syn. Emetin , Emetin a . A feebly basic or alkaloidal body, existing in and forming the active principle of ipecacuanha. Prep. 1. (Medicinal— Emetic Extract .)— a. Ipecacuanha (in coarse powder) is digested first in ether, and then in rectified spirit for 3 or 4 days; the alcoholic tincture is next expre ed and evaporated (distilled) to dryne ; the residuum is di olved in distilled water, and the solution precipitated with acetate of lead; the precipitate is then diffused through distilled water, in a tall gla ve el, and sulphuretted hydrogen is pa ed through it, to throw down the lead; after which the liquor is decanted, filtered, evaporated to the consistence of a thick syrup, and spread in a thin layer on warm plates of gla , and allowed to dry in a current of warm air, or by a gentle heat in a stove. The maceration in ether is frequently omitted. b. Ipecacuanha, 1 part; rectified spirit (·835), 7 parts; make a tincture, distil off the spirit, di olve in cold distilled water, 5 parts; filter the solution, and evaporate, ., as before. Inferior to the last. c. (P. Cod.) As the last, nearly. Obs. Medicinal or impure emetia is brownish, red, deliquescent, and emetic in doses of 1 ⁄ 4 to 1 ⁄ 2 gr. 2. (Pure.)— a. Ipecacuanha (in coarse powder), 1 part, is digested for 24 hours in distilled water, 10 parts; together with calcined magnesia, added in slight exce ; the deposit is then thrown on a filter, washed carefully with very cold water, and dried; it is next di olved in rectified spirit and neutralised with dilute sulphuric acid; the filtered solution is decoloured with animal charcoal, again filtered, and again precipitated by digestion with magnesia; the last deposit forms a colourle solution with rectified spirit, which, by gentle evaporation, gives up its emetia as a yellowish white pulverulent ma , which may be rendered perfectly white by redi olving it in alcohol, ., as before. The proce is rendered easier by first digesting the powdered ipecacuanha in ether. b. (P. Cod.) Alcoholic extract of ipecacuanha, 1 part; water, 10 parts; di olve, filter; add calcined magnesia, 1 part; evaporate to dryne , wash the product on a filter with very cold water, 5 parts; dry it again, and di olve it in boiling alcohol; evaporate the filtered tincture to dryne , redi olve the residuum in a little water, acidulate (slightly) with dilute sulphuric acid, decolour with animal charcoal, filter, precipitate with liquor of ammonia, and dry the precipitate by a gentle heat. c. (Ph. Suec. 1845.) Powdered ipecacuanha, 1 part; water, acidulated with sulphuric acid, 6 parts; digest, filter; add lime, 1 part, and evaporate to dryne over a water bath; the residuum is then exhausted with boiling rectified spirit, and otherwise treated as in the last formula. Prop., . Pure emetia is white, pulverulent, inodorous, and bitter; fusible at 122° Fahr.; very soluble in alcohol and boiling water, but only slightly so in ether, oils, and cold water. It restores the blue colour of reddened litmus, and partially neutralises the acids, forming scarcely crystallisable salts. It is reddened by nitric acid, and this red colour is deepened by ammonia. Tincture of iodine produces a reddish precipitate in an alcoholic solution of emetia. With tincture of galls this solution behaves like morphia; but, unlike the last substance, the salts of iron produce no change of colour in it. These reactions, combined with its emetic properties, are sufficient for its identification.— Dose. White and pure emetia is emetic in doses of 1 ⁄ 20 to 1 ⁄ 16 gr. The large doses ordered in certain pharmaceutical compilations, evidently in error of the difference between the strengths of the pure and the impure or medicinal emetia, have, in several cases which have been reported on, produced very serious consequences. The ‘Journal de Pharmacie et de Chemie,’ for September, 1875, contains a new proce for the extraction of emetia, by M. A. Glenard. This proce is based upon the combined use of lime and ether. It consists in treating with ether a suitably prepared powder, or an extract of ipecacuanha and lime, or the precipitate formed upon adding an exce of lime to a solution obtained by treating ipecacuanha in the cold with water acidulated by sulphuric acid. Either of these mixtures, or the precipitate, when treated with ether, will yield all the alkaloid it contains. The alkaloid may be obtained from the ethereal solution by distilling it to dryne , and treating the residue with acidulated water, or by at once shaking the solution with acidulated water. A more or le acid aqueous liquid is thus obtained, which upon the addition of ammonia, yields the proce ordinarily employed. Preparation of Crystallised Hydro chlorate and Pure Emetine. —When water, acidulated with hydrochloric acid, is employed to remove the emetine from the ether, an acid solution is obtained, which, when sufficiently concentrated by evaporation, forms a nearly colourle , solid, crystalline ma . This ma is formed of extremely delicate needles, formed in bundles that radiate around a central point, and form small spheres with an embo ed surface, resembling mulberries in appearance. Upon pre ing these crystals in a cloth the more or le coloured mother liquid runs off, and the crystals redi olved in water give a colourle solution, from which a fresh crystallisation of perfectly pure hydro chlorate of emetine can readily be obtained. The production of this crystallised hydro chlorate of emetine is worthy of notice, since it does not accord with what has been stated by different authors, who have all considered emetine to be incapable of forming crystallisable salts. It is especially interesting in that it furnishes a convenient and certain method of obtaining perfectly pure emetine, for which it is only nece ary to precipitate a solution of the hydro chlorate with an alkali. But it is important to observe that ammonia does not precipitate all the emetine of the hydro chlorate, and that the precipitate is le in proportion as the salt is more acid. It might appear from this that emetine is soluble in hydro chlorate of ammonia. But the author finds that it is the result of a decomposing action exercised by the emetine upon the hydro chlorate of ammonia, as is shown by the following two experiments. If a little dry powdered emetine be placed in a gla containing a solution of hydro chlorate of ammonia, it may be observed to agglomerate and become transformed into a soft resinoid ma , at the same time the disengagement of ammonia may be recognised, and the resinoid ma gradually undergoes a kind of metamorphosis, and becomes white and crystalline. Again, if emetine in powder be suspended in water, and solution of hydro chlorate of ammonia be gradually added, the emetine is di olved, and upon evaporation of the solution crystals of double hydro chlorate of emetine and ammonia is obtained. The author believes the decomposition of hydro chlorate 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 proce 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 pota ium 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 pota ium, 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 proce . Composition of Emetine and its Hydro chlorate. —These substances dried at 110° C., gave upon analysis results corresponding with following centesimal composition: | Emetine. | Hydro chlorate 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: C 30 H 22 NO 4 . Hydro chlorate of Emetine: C 30 H 22 NO 4 HCl. Preparation and Composition of Emetine (J. Lefort and F. Wurtz, ‘Comptes Rendus,’ lxxxiv, 1299). When ipecacuanha is di olved in water, and a concentrated solution of pota ium nitrate added, a thick ma is produced, consisting of emetine nitrate. It is washed with water, di olved in alcohol, and the solution poured into milk of lime. The mixture is evaporated to dryne , and digested with ether, which di olves out the emetine, leaving it as a yellowish ma on evaporation. On di olving this ma in sulphuric acid, and pouring the solution into dilute ammonia, the alkaloid is obtained as a white precipitate, which is di olved in alcohol, from which it separates in minute radiate groups of needles. By analysis it gave numbers leading to the formula C 28 H 40 N 2 O 3 . [275] [275] Note by the translator (‘Journal of Chem. Soc,’): “This is printed C 28 N 2 H 40 O 5 in the formula for emetine nitrate, and as no data are given, it is impo ible to tell which are correct.” Pure emetine nitrate was prepared, and was found to have the formula C 28 N 2 H 40 O 5 NOH; this in conjunction with Glenard’s results, shows that emetine does not form basic salts.