Investigation of the sustained release of pilocarpine from poly-hema material in suspension form

Abstract

A common approach to reduce (0 the incidence and severity of local and any systemic side effects, (ii) the difficulty of administration, and (iii) the number of applications per day of pilocarpine eyedrops, the conventional treatment of chronic glaucoma, has been to sustain the delivery of the drug to the eye (Chandrasekaran et al., 1978). Phillips and Stone (1990) state that a low water content lens, such as one made from poly-hydroxyethylmethacrylate (HEMA) material, controls intraocular pressure well for up to 12 hours of wear. However, clinical experience, mainly with the Pilocarpine OcusertR, has shown that solid dosage forms suffer from problems of insertion, retention and discomfort, particularly in elderly patients (Salminen 1987; Conn and Langer, 1984). It has in fact been suggested that a critical element in achieving successful commercial use of sustained release systems would be to formulate them in eyedrop rather than insert fonn (Conn and Wise, 1984). For this reason, tests were carried out to investigate the possibility of using an aqueous suspension of pilocarpine-loaded poly-HEMA material as an alternative to a lens in sustaining the release of pilocarpine.