The alkaloids of ipecacuanha. Pt. 3 / by Frank Lee Pyman.

  • Pyman, Frank Lee.
Date:
1918.]
Catalogue details

Licence: Public Domain Mark

Credit: The alkaloids of ipecacuanha. Pt. 3 / by Frank Lee Pyman. Source: Wellcome Collection.

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    apparent in the case of emetine and isoemetine, which differ only in the sign of one asymmetric carbon atom. Dr. H. H. Dale, F.R.S., of the staff of the Medical Research Committee, has kindly determined the relative toxicity of these compounds, and finds that isoemetine is rather less than half as toxic as emetine. The results of intravenous administration of different doses of their hydrochlorides to rabbits were as follows: Emetine hydrochloride. iso Emetine hydrochloride. 4-2~> rngm.* per kilo.—All died. 4*0 ,, ,, —4 died out of 5. .‘1-75 ,, ,, —1 died out of 4. 3-5 or less ,, —All lived. 9-0 mgm.* 8-5 8-25 „ 8-0 „ 7-5 or less per kilo.—All died. ,, —4 died out of (1. ,, —3 died out of 0. ,, —1 died out of 4. „ 1—All lived. * Of the anhydrous salt. With both compounds, death resulted from acute heart failure. It was also found that /soemetine was practically non-emetic for cats. A clinical trial of isoemetine has been carried out by Dr. G. C. Low, to whom the author’s thanks are due. Whilst emetine given in amoebic dysentery nauseates the patient, but brings about the elimination of the amoebae, Dr. Low finds that isoemetine is well tolerated in comparatively large doses, but does not appear to have any effect on the amoebae. Experimental. Isolation of iso Emetine. /.soEmetine occurs together with emetine and base “ C ” amongst the reduction products of methylpsychotrine. In order to isolate it, the syrupy base recovered from the mother liquors of emetine hydrobromide (T., 1917, 111, 439, line 10) is dissolved in alcohol (2 parts) and mixed with a solution of hydrated oxalic acid (0‘5 part) in alcohol (5 parts), and kept for several days, when a spongy, crystalline mass slowly separates. This is collected and washed with alcohol, when crude isoemetine hydrogen oxalate remains. Further quantities remain in the mother liquors from the crystal lisation of the hydrogen oxalate of base “C” (ibid., p. 438). The crude hydrogen oxalate is dissolved in water, and the base regener¬ ated into ether by sodium hydroxide; after removing the solvent, the residue is dissolved in a slight excess of dilute hydrobromic acid, digested with animal charcoal, and filtered, when isoemetine hydro- bromide separates on inoculating and cooling, and is purified readily by recrystallisation from water.