title: Mydriasis from topically administered phenylephrine HCl powder.
abstract: Microgram amounts of finely powdered phenylephrine HCl were administered to the conjunctiva of volunteers. A dose-response curve for white subjects showed a threshold mydriasis of less than 5 micrograms and a clinically useful mydriasis was obtained with one application of 50 micrograms. The time-response curve for the one time use of 50 micrograms of the powder was equivalent to giving three applications of 10% phenylephrine HCl drops. Twenty-five micrograms of pilocarpine HCl powder produced marked miosis. We investigated methods to deliver nonirritating microgram amounts of powdered phenylephrine HCl, pilocarpine HCl, and fluorescein.
mesh_terms: D000328:Adult; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008875:Middle Aged; D009184:Mydriatics / Q000008:administration & dosage*; D009883:Ophthalmic Solutions; D014677:Pharmaceutical Vehicles; D010656:Phenylephrine / Q000008:administration & dosage*; D011208:Powders; D011680:Pupil / Q000187:drug effects*
chemical_list: D009184:Mydriatics; D009883:Ophthalmic Solutions; D014677:Pharmaceutical Vehicles; D011208:Powders; D010656:Phenylephrine