Effects on intraocular pressure and pupil size in glaucomatous beagles after topical pilocarpine instilled with standard (pH 5) and buffer-tip (pH 7) droptainers.

Single doses (50 microliters) of 1% and 2% pilocarpine, instilled by a buffer-tip droptainer resulting in an approximate pH 7.0 solution, and 1, 2, and 4% pilocarpine, instilled by the standard droptainer, resulting a pH 5.0 solution, were evaluated in the glaucomatous Beagle model. Pupil size and intraocular pressure measurements were performed at 0, 1/4, 1/2, 3/4, 1, 2, 4, 6, and 8 hours. Signs of topical irritation (blepharospasm, conjunctival hyperemia and chemosis, and any corneal changes) were also monitored. Both solutions produced similar onset and duration of miosis and ocular hypotension, but the pH 5.0 solutions produced a brief elevation in intraocular pressure during the first hour post-drug instillation. Moderate blepharospasm, conjunctival hyperemia, and chemosis occurred with only the pilocarpine solutions with pH 5.0.