Self-curing controlled release systems for steroids. Application of prednisolone-based polymeric systems to ear diseases

Abstract

An injectable delivery system for prednisolone has been prepared based on a self-curing formulation comprised of poly(methyl methacrylate) particles and hydroxyethyl methacrylate as monomer. The polymerisation reaction was initiated by the redox system 4,40-bis (dimethylaminobenzydrol)/benzoyl peroxide (BZN/BPO) and followed at 25 1C by measuring the time–temperature profile. A maximum temperature of 53 1C and a setting time of 15 min were obtained, calculated according to standard specifications. The swelling of the cured system was studied in phosphate-buffered saline (PBS) at 37 1C giving a hydration degree at equilibrium of 20%. The swelling kinetics fitted a fickian behaviour at the initial stages of the experiments, with a diffusion coefficient of 0.72 10 7 cm2/s. The release of the drug was sustained from the beginning without an initial drug burst. The study of the wettability showed a rather hydrophilic character of the surface of the loaded system, and the biocompatibility evaluated through MTT assay revealed the absence of cytotoxicity due to the release of toxic substancesFinancial support from the Comisio´ n Interministerial de Ciencia y Tecnologı´ a, CICYT (MAT2002-04147- C02-02) is gratefully acknowledgedPeer reviewe