2. Expressed juice of belladonna is evaporated over a water-bath to the consistence of an extract, and then triturated in a marble or porcelain mortar with a strong solution of caustic potassa; the resulting mass is digested and well agitated for some time, at the temperature of 75° to 80° Fahr., with benzole, q. s.; and, after repose, the benzole-solution is carefully separated, and its volatile hydrocarbon is distilled off by the heat of a water-bath; the residuum in the retort is now exhausted with water acidulated with sulphuric acid, and the resulting ‘acid-solution,’ after filtration, precipitated with carbonate of soda; the precipitate is crude ATROPIA, which is collected
on a filter, pressed between folds of bibulous paper, and dried; after which it is purified by one or more re-solutions, in alcohol, and crystallisations, which may or may not be modified in the manner noticed. The proportion of potassa should be about 1 dr. to every quart of the expressed juice. An excellent and economical process. The product is 0·3 to 4% of the weight of the plant from which the juice has been obtained.
3. (Mein and Liebig.) Belladonna-root (fresh-dried and coarsely powdered) is exhausted by alcohol (sp. gr. 0·822); slaked lime (1 part for every 24 of the dried root employed) is then added to the tincture, and the whole digested, with agitation, for 24 hours; sulphuric acid is next added, drop by drop, to slight excess, and, after filtration, rather more than one half the spirit is removed by distillation; a little water is now added to the residue, and the remainder of the alcohol evaporated as quickly as possible by a gentle heat; after again filtering, the liquid is reduced by further evaporation to the 1⁄12th part of the weight of the root employed, and a concentrated solution of potassa dropped into the cold liquid (to throw down a dark greyish-brown matter), carefully avoiding excess or rendering the liquid in the slightest degree alkaline; in a few hours the liquid is again filtered, and carbonate of potassa added as long as a precipitate (ATROPIA) falls; after a further interval of from 12 to 24 hours, this precipitate is collected and drained in a filter, and after pressure between folds of blotting-paper, dried by a very gentle heat. It is purified by making it into a paste with water, again squeezing it between the folds of blotting-paper, drying it, re-dissolving it in 5 times its weight of alcohol, decolouring it with pure animal charcoal, distilling off greater part of the alcohol, and evaporation and crystallisation by a very gentle heat; or only about one half the spirit is distilled off, and 3 or 4 times its volume of water gradually agitated with it, the resulting milky liquid being then heated to boiling, and allowed to cool very slowly, when nearly the whole of the ATROPIA crystallises out after a few hours. The same may be effected by at once agitating 6 or 8 volumes of water with the alcoholic solution, and setting aside the mixture for 12 to 24 hours, by which time the crystallisation will be completed. This process originated with Soubeiran, was improved by Mein, and subsequently, with slight modifications, adopted by Liebig. The product is about 0·3% of the weight of root operated on.
4. (Bouchardat and Cooper.) The filtered tincture is precipitated with iodine dissolved in an aqueous solution of iodide of potassium, the resulting ioduretted hydriodate of atropia, decomposed by zinc-and-water, the metallic oxide separated by means of carbonate of potassa, and the alkaloid thus obtained dissolved in alcohol and crystallised.
5. (Mr Luxton.) The dry leaves of belladonna are gently boiled for 2 hours in distilled water just sufficient to cover them, and the resulting decoction is strained through a coarse cloth into a large precipitating jar; this process is repeated with a second quantity of distilled water, and the two decoctions mixed; concentrated sulphuric acid is now added in the proportion of 2 dr. to every pound of leaves operated on, by which the vegetable albumen of the decoction is precipitated, and the liquid becomes clear and sherry-coloured; the clear liquor is now decanted or syphoned off, and, if necessary, filtered; the filtrate is now decomposed by either passing a stream of gaseous ammonia through it, or by suspending in it a lump of carbonate of ammonia. The effect is that the liquid turns black, and crystals of ATROPIA are slowly formed and deposited. At the expiration of a day or two, the supernatant mother-liquid is removed with a syphon, and the crystals thrown on a filter to drain and dry.[102] It may be purified by re-solution and crystallisation. 1 lb. of leaves yields 40 gr.; or at the rate of fully ·57%.
[102] ‘Pharm. Journ.,’ 1854-5, p. 209{?}.
6. (Rabourdin.) To the crystallised juice of the plant (previously heated to coagulate its albumen, filtered, and allowed to cool), 1 quart, is added of caustic potassa 1 dr., and afterwards of chloroform 1 oz.; the whole is then agitated well, and after half an hour’s repose, the supernatant liquor is poured from the discoloured chloroform, which, after being washed with distilled water as long as it gives any colour to that liquid, is placed in a small retort, and the chloroform distilled off by the heat of a water-bath; the residuum is dissolved in a little water acidulated with sulphuric acid, and precipitated with carbonate of potassa, in slight excess; the precipitate is redissolved in alcohol, and the solution, by spontaneous evaporation, yields crystals of ATROPIA.
7. (Ure.) From the expressed juice of the fresh, or the watery extract of the dry plant, by treating it with caustic soda, in slight excess, and then agitating the mixture with 1½ times its volume of ether; the ATROPIA taken up by the ether is again deposited after repose for some time, and is then purified by repeating the treatment with fresh ether as often as necessary.
8. Freshly precipitated hydrate of magnesia is added to the coagulated and filtered expressed juice, and the mixture evaporated to dryness, as quickly as possible, in a water-bath; the residuum is pulverised and digested in strong alcohol, and the clear liquid allowed to evaporate spontaneously. The crystals may be purified by repeated re-solutions in alcohol.
Prop., Tests, &c. The crystals obtained from hot concentrated solutions, colourless, transparent, silky prisms; from solutions in dilute spirit, silky needles, like those of disulphate