Bioavailability of timolol and aceclidine after ocular instillation in the rabbit

The bioavailability of timolol and aceclidine after the ocular instillation of each drug (timolol 0.5% or aceclidine 2%) or both combined (timolol 0.5% + aceclidine 2%) has been evaluated in rabbits. 15 male albino rabbits were treated by the instillation of timolol and aceclidine alone or combined in the conjunctival sac of the right eye. Timolol concentrations in humor aqueous were assayed at 10 min, 30 min, 1 hr, 2 hr, 4 hr and 6 hr after instillation by high-performance liquid chromatography (HPLC). Aceclidine was assayed by a pharmacodynamic method: pupillary diameter at the following time intervals 0 (basal value), 1 min, 5 min, 30 min, 1 hr, 2 hr, 4 hr, 6 hr after treatment. Our results demonstrated that no differences in timolol and aceclidine bioavailability were found between simple-drug preparations and their combination.