Homatropine is a synthetic analogue of the natural alkaloid atropine and is prepared by esterification of mandelic acid with 3α-tropine. Its range of action corresponds to atropine. However, the effect of homatropine is 10 times weaker than that of atropine and its toxicity decreases correspondingly.1
C2 PHARMA is one of the leading manufacturers and suppliers of homatropine hydrobromide. The API is synthesized chemically.
Homatropine HBr as a 2% or 5% ophthalmic solution is used to induce mydriasis (dilation of the pupil) and cycloplegia (paralysis of accommodation) as a result of its local anticholinergic effects on the ciliary muscle and iris. It is used prior to retinoscopy.2
MECHANISM OF ACTION
Homatropine inhibits the muscarinic actions of acetylcholine in the structures innervated by postganglionic cholinergic nerves, as well as in smooth muscles that respond to acetylcholine but lack cholinergic innervation.3 By blocking muscarinic receptors and cholinergic signaling pathways, Homatropine blocks the response of the iris sphincter muscle and causes the pupil to become unresponsive to light, leading to mydriasis. It also blocks cholinergic stimulation of the accommodative muscle of the ciliary body.2
- Christen, P. Stud. Nat. Prod. Chem. 2000, 22, 717-749.
- Rang, H. P., Dale, M. M. Rang and Dale’s Pharmacology (7th ed., 2012). Edinburgh: Elsevier/Churchill Livingstone (ISBN 978-0-7020-3471-8).