Extraction of Atropine

Naturally occurring hyoscine is a combination of laevo-tropic acid with inactive hyoscine. It is found, mostly in conjunction with hyoscyamine, in many species of Datura. In D. arborea, D. fastuosa, and D. metel, the alkaloid consists chiefly of hyoscine whilst D. stramonium contains principally hyoscyamine, with some hyoscine. It is present also in Scopolia and Hyoscyamus species, for instance in Scopolia japonica and Hyoscyamus niger. 

Datura metel is probably the most readily available source of hyoscine. The powdered drug is extracted with hot alcohol and the crude alkaloids are isolated in the same way as has been described under hyoscyamine, except that sodium bicarbonate is employed, instead of ammonia, for liberating the bases. The alkaloid is neutralised exactly with hydrobromic acid and the solution of the hydrobromide concentrated. The salt which crystallises out on cooling is separated and purified by recrystallisation from water, until of constant melting point. 

In 1809, Vaquelin discovered atropine. Brandes recognized atropine as an alkaloid in 1819. Atropine only occurs in trace amounts in plants, but is readily obtained from the racemitization of levorotatory hyoscyamine which is abundant in nightshade family. Common sources are belladonna root, Jimson Weed, Hyoscyamus niger and H. muticus. 

The plant material is powdered and an aqueous solution of sodium carbonate is added to thoroughly moisten. 

Ethyl ether or ethyl acetate are percolated through the mixture. Acetic acid is used to extract the bases from the solvent. The acetic acid/ base solution is washed with ether until the ether absorbs no more color. The bases are precipitated with sodium carbonate, washed, dried and dissolved in ethyl ether. 

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The method involves extraction of atropine and a homatropine internal standard from the aqueous phase which is rendered alkaline by the addition of ammonia followed by trimethylsilylation with A, Obistrimethylsilyl acetamide (BSA). 

MajlSt worked out a gas chromatographic assay of atropine and phenobarbital in pharmaceutical preparations containing Valeriana liquid extract. After extraction of atropine, it was hydrolyzed and the free tropic acid silylated with N,0-bis(trimethylsilyl(acetamide. The assay was performed on a glass column, 1 m long by 3 mm I.D. packed with 1.5 % OV-101 on silanized Gas Chrom P, 100-120 mesh, at 140°C, using silylated 2-naphtol as an internal standard. 

By extraction of Solanacean drugs, especially Atropa belladonna, Hyoscyamus niger or other species. On careful extraction L-hyoscyamine is obtained first, which can be racemized to atropine by addition of alkali in ethanolic solution. 

The profound physiological effects of alkaloids have been known for centuries. For example, Socrates was put to death with an extract of hemlock, which contains a poisonous alkaloid, coniine. Other alkaloids have long been valued for their beneficial medical effects. Examples include morphine (a painkiller), quinine (used to treat malaria), and atropine (used to treat Parkinson s disease and in eye drops that dilate the pupils). 

Kleinwachter I. Observations concerning the effectiveness of extract of calabar against atropine poisoning. Berl khn Wschr. 1 369-377, 1864. 

In contrast to muscarine, atropine blocks these actions of acetylcholine and muscarine. Atropine is, therefore, an acetylcholine antagonist. It binds where acetylcholine binds and therefore prevents the binding of the latter but does not activate it. Two molecules cannot occupy the same binding site at the same time. Atropine is isolated from the plant Atropa belladonna. Extracts of this plant have been used for millennia for a variety of purposes. Although large doses are poisonous (Atropos is the name of the Fate who cuts the thread of life), small doses causes dilation of the pupils, a consequence of its action as an acetylcholine antagonist, and has been used for cosmetic purposes by women, hi Itahan, belladonna means beautiful woman. 

Hypotensive activity. Essential oil, administered intravenously to dogs at a dose of 3 p,L/kg, was active. The ethanol (70%) extract, administered intravenously to dogs at a dose of 75 mg/kg, was active. There was a dip followed by rise in blood pressure° . Ethanol (80%) extract of the aerial parts, at a dose of 10 mg/kg, was not blocked by atropine. The extract did not inhibit pressor response of norepinephrine either . Ethanol (95%) extract of the seed, administered intravenously to dogs at a dose of 10 mg/kg, produced a transient effect that was blocked by atropine ". Petroleum ether fraction chromatographed and fraction eluted with chloroform, administered intravenously to rabbits at a dose of 0.80 mg/kg, was inactive. Methanol extract, administered intravenously to dogs and rabbits at a... 

Antispasmodic activity. Gum extract, administered to isolated guinea pig ileum at a dose of 3 mg/mL, produced a decrease of spontaneous contraction to 54 7% of control. Exposure of precontracted ileum by acetylcholine, histamine, and KCl to Ferula gum extract produced a concentration-dependent relaxation. Preincubation with in-domethacin, propanolol, atropine, and chlorpheniramine before exposure to the gum, did not produce any relaxation " . Antitumor activity. Water extract of the dried oleoresin, administered by gastric intubation to mice at a dose of 50 mg/ani-mal daily for 5 days, was active on CA-Ehrlich ascites, 53% increase in life span Water extract administered intra-peritoneally was inactive on Dalton s lymphoma, 4.8% ILS, and CA-Ehrlich ascites, 5.5%... 

Hypotensive effect. Methanol (70%) extract of the seed, administered intravenously to rats at dose of 3 mg/kg, was active. The effect was inhibited by pretreatment with atropine . 

All parts of the belladonna plant contain the alkaloids. Linne named the species after one of the Fates, Atropos, who cut the thread of life. In Italy during the Middle Ages an extract of the plant was dropped onto the eyes in order to dilate the pupils (this practice gave rise to the name "belladonna" or beautiful lady since large dark pupils were considered a mark of beauty). Today atropine analogues, such as homatropine, are still used to dilate the pupils for opthalmalogical studies. Sympathomimetics can also be used for this purpose. See the Aside on Eye Openers . 

The prototypical antimuscarinic anticholinergic drug is atropine (Fig. 19-2). Atropine is a naturally occurring substance that can be obtained from the extract of plants such as belladonna and jimsonweed. Other natural, semisynthetic, and synthetic antimuscarinic anticholinergic agents have been developed that are similar in structure or function to atropine. 

The alkaloids of this group are derived from a combination of a piperidine and a pyrrolidine ring, designated as tropane (Figure 14.2). The 3-hydroxy derivative of tropane is known as tropine and is the basic component of atropine. When atropine is hydrolyzed, it forms tropine and tropic acid (a-phenyl-p-hydroxy-propionic acid). Atropine is the tropic acid ester of tropine. It has been prepared synthetically. Tropic acid contains an asymmetric carbon atom. The racemic compound (atropine) as obtained naturally or as synthesized may be resolved into its optically active components, d- and /-hyoscyamine. Atropine is racemic hyoscyamine that is, it consists of equal parts of /-hyscyamine and plant cells and also in the process of extraction, so that the relative proportion of the isomers in the plants and in the preparations varies. However, atropine itself does exist in small amounts in the plants, although most of it is formed from the /-hyoscyamine in the process of extraction. 

Dimitrov, K., Metcheva, D. and Boyadzhiev, L. (2005) Integrated processes of extraction and liquid membrane isolation of atropine from Atropa belladonna roots. Separation and Purification Technology, 46, 41. 

In addition to the silica-based materials mentioned above, modem polymers are widely used for TTA and QTA sample preparation allowing SPE not impaired by undesirable silanol activities. HLB Oasis (Waters) is the tradename for a hydrophilic-lipophilic balance reversed-phase sorbent enabling lipophilic interaction to benzene moieties and hydrophilic interactions to pyrrolidone groups as present in the macroporous copolymer of poly(divinylbenzene-co-iV-vinylpyrrolidone). Elution of analytes is often performed with solvents containing MeOH or ACN. Applying this adsorbent TA such as atropine and scopolamine were extracted from human viscera [15], human serum [97-99], human urine [12] as well as from rat plasma and brain microdialysate [77], Furthermore, this hydrophilic-lipophilic balance phase was also suitable for extraction of the QTA trospium from human and rat plasma [77, 84] and methyl scopolamie from rat plasma [77] (Table 4). 

Cyclodextrins and modified cyclodextrins are widely used as chiral selectors [51]. For an example, the enantiomers of atropine, a main ingredient of Scopolia extract and Scopolia rhizome, was separated by capillary electrophoresis with cyclo dextrin media [52]. 

Anticholinergics, such as atropine and oxyphenonium bromide, which are esters of carboxylic acids, were analysed in plasma and urine as pentafluorobenzyl esters [541,542], The method involves ion-pair extraction of the material under analysis, hydrolysis of esters and derivatization of the acid moiety. The minimal detectable amount was found to be 0.15 pg with the use of an ECD. 

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