The methonium compounds / by W.D.M. Paton and Eleanor J. Zaimis.

  • Paton, William D. M.
Date:
[1952?]
Catalogue details

Licence: In copyright

Credit: The methonium compounds / by W.D.M. Paton and Eleanor J. Zaimis. Source: Wellcome Collection.

    3/36 (page 221)
    specific compounds: decamethonium, imitating acetylcholine very closely at the neuromuscular junction of certain species; and hexamethonium, specifically antagonising acetylcholine at the ganglionic synapse. II. Physical and Chemical Properties The methonium di-iodides are white crystalline solids, not markedly hy¬ groscopic, very soluble in water, and form neutral solutions. The solubility of the octadecane derivative, the only higher member so far synthesized, is lower than that of the other members of the series, as would be expected. The di¬ iodides are stable in aqueous solutions, and can be sterilized by boiling or auto¬ claving. They may be boiled with acid or alkali without destruction. The dibromides have the same properties as the di-iodides except for being both hydrated and hygroscopic. The dichlorides are still more hygroscopic than the bromides, their lower members often being difficult to dispense in the solid state (134). The uptake of moisture depends in part on the method of preparation. The bitartrate and methosulphate salts have also been prepared (8’ 12)‘ The lower members of the methonium series have negligible surface activity; with dodecamethonium and tridecamethonium a distinct depression of the surface-tension of water is observed which becomes substantial with the oc¬ tadecane derivative. The methonium salts form insoluble salts with ammonium reineckate, and their isolation from body fluids and photoelectric determination are based on this property (185). Sparingly soluble salts of hexamethonium are formed with 2:2' - dihydroxy -1:1'- dinaphthyl methane - 3:3' - dicarboxylic acid (“embonic acid5’) and with its next lower homologue (“bis-oxynaphthoic acid”), and these have proved useful in the isolation of hexamethonium from mixtures (13). All the soluble salts have been successfully given intravenously, intramuscu¬ larly, subcutaneously and orally. They are non-irritant unless given in strongly hypertonic solution (e.g., 30%). The incorporation of hexamethonium in a delay- medium of polyvinyl-pyrrolidone (20%) has been used, but absorption from the site of injection is only slightly prolonged (118). III. Estimation Colorimetric and biological methods have been described for the detection of methonium compounds in urine, faeces and blood. Zaimis (185) has described a photoelectric method for the determination of methonium ions, after their precipitation as reineckates. The method may be applied to urine or faeces. At least 10 mg. of methonium salt is required for an adequate estimation. The technique is therefore not sensitive enough to analyse the methonium content of the blood. The reaction used for the detection of small amounts of tetraethylammonium does not proceed for the methonium series. For detecting low dilutions of hexamethonium, a biological method must be used. Two procedures have proved successful (129): (a) use of the antagonism