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

摘要

An injectable delivery system for prednisolone has been prepared based on a self-curing formulation comprised of poly(methyludmethacrylate) particles and hydroxyethyl methacrylate as monomer. The polymerisation reaction was initiated by the redox systemud4,40-bis (dimethylaminobenzydrol)/benzoyl peroxide (BZN/BPO) and followed at 25 1C by measuring the time–temperature profile.udA maximum temperature of 53 1C and a setting time of 15 min were obtained, calculated according to standard specifications. Theudswelling of the cured system was studied in phosphate-buffered saline (PBS) at 37 1C giving a hydration degree at equilibrium ofud20%. The swelling kinetics fitted a fickian behaviour at the initial stages of the experiments, with a diffusion coefficient ofud0.72 10 7 cm2/s. The release of the drug was sustained from the beginning without an initial drug burst. The study of theudwettability showed a rather hydrophilic character of the surface of the loaded system, and the biocompatibility evaluated throughudMTT assay revealed the absence of cytotoxicity due to the release of toxic substances