ATROPINE

Brand Names: DL-Hyoscyamine; Tropic acid ester with tropine, DL-Tropyl tropate, Tropine tropate.

Atropine is extracted from  Atropa belladonna L., Datura stramonium L., Hyoscyamus CH, Oh muticus or Duboisia species, or prepared by synthesis. During extraction, partial racemization of the l-hyoscyamine takes place which is completed by treatment with dilute alkali on heating in chloroform solution.

Atropine is the tropylester of tropic acid, C6H5CH (CH2OH) COOH. For the synthesis of atropine, tropinone is reduced under proper conditions to tropine. which is then used to esterify tropic acid.

Atropine, m.p. l l 4-118°, is an odourless, white crystalline powder; sparingly soluble in water, readily in alcohol, ether and chloroform. Atropine is optically inactive. It is a monoacid tertiary base, and forms salts with acids. In the presence of acids or alkalies, atropine is hydrolyzed to tropine and tropic acid.

Atropine is soluble in water (1 in 460), alcohol (1 in 2), chloroform (1 in 1) and ether (1 in 25). A saturated aqueous solution is alkaline to phenolphthalein.

Atropine sulphate (Atropisol) : It is prepared by neutralizing atropine in acetone or ether solution with an alcoholic solution of sulphuric acid. The salt occurs as a white crystalline powder; is soluble in water and alcohol; practically insoluble in chloroform and in ether. Aqueous solutions are unstable and should be freshly prepared. Stability is increased in acid solutions of pH below 6; solutions should be protected from alkalies. It is efflorescent in dry air and should be protected from light to prevent deterioration. Atropine and its salts are stored in airtight containers and protected from light.

Uses:

1.      Atropine is anticholinergic, and antimuscarinic alkaloid, has antispasmodic action on smooth muscles and reduces secretions and perspiration.

2.     It is used to alleviate the griping caused by vegetable laxatives, in the treatment of smooth muscle spasm, in the symptomatic treatment of parkinsonism, to reduce tremor sialorrhoea and muscular rigidity, and to improve the gait, posture and speech. The antispasmodic action of atropine has been used to facilitate radiological examination of the gut. It depresses the vagus and is used as cycloplegic and mydriatic, in the treatment of iritis and uveitis to immobilize the ciliary muscle and iris.

3.     Atropine has been used in the form of liniment to relieve the pain of muscular rheumatism, sciatica and neuralgia.

4.     Atropine is a specific antidote to prevent the 'muscarinic' effect of acetylcholine accumulation such as vomiting, abdominal cramps, diarrhoea. salivation. sweating, bronchoconstriction and excessive bronchial secretion.

Side Effect

Side effects of atropine and other antimuscarinic agents include dryness of mouth, thirst, dilation of the pupils, flushing and dryness of the skin, bradycardia, reduction of tone, constipation, etc. Sometimes vomiting, giddiness and staggering may occur. Toxic doses cause tachycardia, rapid respiration, hyperpyrexia and CNS stimulation.