C15H21NO2 = 247.178.
Emetine or methyl-cephaeline, is an alkaloid contained in ipecacuanha root. It occurs as an amorphous white powder, with a bitter taste, darkening on exposure, and gradually assuming a Yellow colour. Melting-point, 69°. It is strongly alkaline to litmus, and forms crystallisable salts with acids. Its insolubility in caustic alkalies distinguishes it from cephaeline. Emetine hydrobromide occurs in white crystals, C15H21NO2, HBr, 2H2O, soluble in water, but less so than the hydrochloride, difficultly soluble in absolute alcohol or chloroform.
Soluble in alcohol, ether, chloroform, benzene, or fixed oils; slightly soluble in water, and hot petroleum ether; insoluble in essential oils and caustic alkaline solutions.
Action and Uses.—Emetine has the expectorant action of ipecacuanha; it is, however, less powerfully emetic and but half as toxic as cephaeline. It is used chiefly in the form of hydrochloride. Emetine is probably not so good a remedy as the crude preparations of ipecacuanha, since the alkaloid is more readily absorbed, whilst the effects of the drug on the alimentary canal are produced without absorption. The alkaloid emetine and its salts must be distinguished from the extractive, emetin, the expectorant dose of which is 3 to 6 milligrams (1/20 to 1/10 grain).