The hydrobromid of an alkaloid, tropin mandelate, produced synthetically.

Properties : It usually occurs as a white, odorless, crystalline powder, having a bitter taste. It is freely soluble in water (1:5.7) and soluble in alcohol (1:32.5).

Incompatibilities : Homatropin hydrobromid has the ordinary incompatibilities of the salts of alkaloids.

Action and Uses: The actions of homatropin are identical with those of atropin,. except for the fact that the mydriasis produced by it occurs more promptly and disappears in about eighteen hours. When applied freely to the conjunctiva it may be absorbed so that the bitter taste can be perceived, but the throat does not become dry as after atropin. The effect of this drug is increased by mixture with cocain.

Dosage: 0.0005 gm. or 1/125 grain. Homatropin is used chiefly as a mydriatic in place of atropin. It may be used in aqueous solution of 2 per cent, strength, or a drop of a 1:500 solution may be introduced into the conjunctival sac every five minutes for five times to produce a maximum \ dilatation in three-quarters of an hour. This will return to normal in from fourteen to eighteen hours.