The Mydriatic Effect of Intracameral Epinine Hydrochloride
Björn Lundberg 1
and
Anders B Behndig 2*
1 Clinical Sciences/Ophthalmology, Umeå University, Umeå, Sweden
2 Clinical Sciences/Ophthamology, Umeå University, Dept. of Clinical Sciences/Ophthalmology, Umeå University Hospital, Umeå, SE-901 85, Sweden
* To whom correspondence should be addressed. E-mail: anders.behndig{at}ophthal.umu.se.
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Abstract |
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PURPOSE. To compare the mydriatic effect and the short-term corneal endothelial safety of intracamerally injected N-methyl-3,4-dihydroxyphenylamine (epinine) to phenylephrine in a porcine eye model.
METHODS. One hundred and twelve eyes from newly slaughtered pigs were used in this study. After pretreatment with 20 mg of intracameral acetylcholine to give miosis, 0.15 ml of epinine or phenylephrine 0.3%, 1.5% or 3.0% was given as an intracameral injection. The pupils were filmed during 90 seconds with a video camera connected to an operation microscope, and the mean pupil diameters were measured from the video recordings. In 37 additional eyes, 0.15 ml of the vehicle, 1.5% epinine or 1.5% phenylephrine was injected intracamerally, and the eyes were kept on ice overnight. Corneal endothelial morphology was assessed before and after the treatment. Ten eyes were given no injection and served as controls.
RESULTS. Epinine had a significantly larger mydriatic effect than phenylephrine at equal concentrations. The endothelial cell loss was equal with both substances, and did not exceed that of the vehicle.
CONCLUSIONS. Epinine was a more potent mydriatic than phenylephrine in this porcine eye model. The porcine eye model appears suitable as a first efficacy screening of substances for intraocular use. Epinine is a promising candidate substance for intraoperative intracameral use in humans, for example in cataract surgery.
Key Words:
pharmacokinetics, iris, drug delivery, receptors
