Digitalis assay / by W. Harrison Martindale.

  • Martindale, W. Harrison (William Harrison), 1874-1933.
Date:
1913
Catalogue details

Licence: In copyright

Credit: Digitalis assay / by W. Harrison Martindale. Source: Wellcome Collection.

    7/54 (page 5)
    Tannin Compounds and takes up the glucosides). Distil in vacuo—the syrupy residue contains all the water-soluble glucosides. The syrup (still warm) is shaken up with 100 Gm. of water, and after standing over night is filtered. A small amount of Anhydrogitalin remains as precipitate. Shake the Aqueous solution 20 times (five times is in reality sufficient) each with 40 Gm. Chloroform. Saponins remain behind whilst an active glucoside goes into solution. The Chloroform Ex- tractive is dried by Sodium Sulphate and distilled in vacuo yielding crude water-soluble active glucoside. The new active glucoside Gitalin can, it is stated, be prepared direct from the purified Aqueous extractive, as follows :—Shake out with Chloroform; shake the chloroformic extractive with dry Soda and exsiccated Sodium Sulphate and then pour the Liquor into Petroleum Ether. Filter off the glucoside which is thrown out, dry it, purify by rapid crystallisation from cold dilute Alcohol, dissolve again in Chloroform, precipitate by adding to Petroleum Ether to obtain the easily soluble amorphous water- free modification—Gitalin. The Saponins are fully described in the paper to which I refer—one of these appears identical with Schmiedeberg’s Amorphous Digitonin, Syn. Digitsaponin Kraft, as already indicated. PEOPEETIES OF GITALIN. Gitalin is described as an amorphous, white water-soluble glucoside (soluble 1 in 600 in cold water), insoluble in Petroleum Ether. A crystalline Hydrate can be prepared more soluble in cold than hot water, m.p. 150-155°. Gitalin rapidly decomposes in presence of almost all solvents except Chloroform and cold water. On heating a solution or keeping a solution in any solvent, except Chloroform, a precipitate forms which contains IH2O less, i.e., Anhydrogitalin. This body is insoluble in most liquids. The yield of Gitalin is stated to be about 0’01%.