This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
B. P., not official. C16H21No3hbr=355.l7. The hydrobro-mate of an alkaloid prepared from Tropine. Homatropine is really Oxytoluyl-tropine.
1) Tropine, C8H15NO, a derivative of Atropine, is heated with Oxytoluic Acid in the presence of Hydrochloric Acid; (2) Ammonia is added, and pure Homatropine shaken out with Chloroform; (3) the Chloroformic solution is evaporated; (4) the Homatropine is neutralized with Hydrobromic Acid.
Small prismatic white crystals.
In 10 parts of water; in 133 parts of Alcohol.
Dose, 1/120 to 1/20 gr.; .0005 to .003 gm. subcutaneously.
Homatropine hydrobromate has an action exactly similar, so far as we know, to that of atropine. It is only used to dilate the pupil in ophthalmic practice, the advantage over atropine being that the dilatation produced by homatropine passes off in a quarter of the time. It may be applied as a solution, 1 in distilled water 120. Sometimes a solution in castor oil is used, for it is less likely to be washed out by the tears, but it may be rather irritating.