Relative bioavailability of pilocarpine from a novel ophthalmic delivery system and conventional eyedrop formulations

Pupillary responses to pilocarpine following topical application in a novel ophthalmic delivery system (NODS) and a conventional eyedrop formulation have been compared in eight healthy subjects in a single dose crossover study. The magnitude of the miotic and light reflex responses to NODS 40, 80, and 170 micrograms and to a single 2% Minims eyedrop (delivering 518 micrograms) were recorded by infrared television pupillography over periods of 24 hours. Dosage comparisons of drug responses were obtained by interpolation and yielded the equivalence of one eyedrop to 67 +/- 11 micrograms pilocarpine from the NODS formulation. These findings indicate that in a comparison of total doses delivered pilocarpine has an approximately eight-fold greater bioavailability from NODS than from a conventional eyedrop formulation.