HOMATROPINE

HOMATROPINE

Brand Names : Mandelyltropeine, Tropine mandelate.

Homatropine is a synthetic alkaloid which is a lower homologue of atropine. It is prepared by the interaction of tropine and mandelic acid.

Homatropine, m.p. 99-100°, occurs as colourless, odourless crystals or a white crystalline powder. It is hygroscopic, but only slightly soluble in water; soluble in alcohol, benzene, chloroform, ether, acetone and dilute acids.

The hydrobromide or hydrochloride is obained readily from the free base by neutralizing with hydrobromic or hydrochkoric acid. The hydrobromide occurs as colourless, odourless crystals or a white crystalline powder. It is soluble in water and alcohol; slightly soluble in chloroform; very slightly soluble in ether; stored in airtight containers and protected from light.

Homatropine methylbromide, m.p. 210-212°, is the tropine methylbromide ester of mandelic acid. It is prepared by treating homatropine with methyl bromide, thus yielding the quaternary compound. It occurs as a white, bitter, odourless powder that slowly darkens on exposure to light. It is very soluble in water, freely soluble in alcohol; practically insoluble in acetone and ether.

Uses

Homatropine is is an antimuscarinic agent , has antispasmodic action on smooth muscles and reduces secretions and perspiration. 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.

When applied to the eye its cycloplegic and mydriatic actions are more rapid and of shorter duration. In combination with ammonium methobromide, homatropine is used to treat peptic ulcer and gastro-intestinal spasm.

Side Effect

Side effects of homatropine  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.