Purpose: Two features define the future of glaucoma therapeutics: (1) greatly improved ocular hypotensive efficacy and (2) a delivery method that improves patient convenience and compliance. A highly efficacious and extraordinarily long-acting ocular hypotensive agent PGN 9856-isopropyl ester represents a potential next-generation anti-glaucoma drug. A new periorbital drug delivery route was also investigated. Methods: PGN 9856-isopropyl ester pharmacology was determined by employing human cells, including prostanoid receptor transfectants, and FLIPr or cellular dielectric spectroscopy technology. Intraocular pressure (IOP) was measured in conscious cynomolgus monkeys trained to accept pneumatonometry when under gentle restraint. For periorbital application, the compound was applied radially using a roller-ball device connected to a cylindrical reservoir. Pharmacokinetic data were obtained using LC/MS/MS instrumentation. Results: Single doses of PGN 9856-isopropyl ester, administered over a 0.001%-0.01% dose range, produced profound decreases in monkey IOP that persisted for at least 5 days, which was long after the drug was detectable in ocular tissues. It was not uncommon for a single eye drop to reduce IOP to the level of 4-7 mm Hg. Drug application to the periorbital dermis of ocular normotensive monkeys produced a similarly profound reduction in IOP, which was well maintained. Conclusions: PGN 9856-isopropyl ester appears to possess efficacy and duration of action properties unmatched by currently prescribed anti-glaucoma agents and by those currently undergoing clinical evaluation. In addition, application to the periorbital skin using a roller-ball device offers a more convenient method of ophthalmic drug delivery than eye drops and is noninvasive, unlike other "dropless" technologies.
Keywords: EP receptor agonist; glaucoma animal model; pharmacology.