title: 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 4,4'-bis (dimethylaminobenzydrol)/benzoyl peroxide (BZN/BPO) and followed at 25 degrees C by measuring the time-temperature profile. A maximum temperature of 53 degrees C 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 degrees C 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 x 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 substances.
authors.affiliation: Instituto de Ciencia y Tecnología de Polímeros, CSIC, C/Juan de la Cierva, 3, 28006 Madrid, Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Fernandez
authors.forename: Juan
authors.initials: J
authors.lastname: Parra
authors.forename: Blanca
authors.initials: B
authors.lastname: Vazquez
authors.forename: Antonio
authors.initials: A
authors.lastname: Lopez-Bravo
authors.forename: Julio San
authors.initials: JS
authors.lastname: Román
mesh_terms: D000818:Animals; D001585:Benzoyl Peroxide / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry*; D004396:Coloring Agents / Q000494:pharmacology; D004058:Diffusion; D004337:Drug Carriers; D016503:Drug Delivery Systems; D004427:Ear Diseases / Q000188:drug therapy*; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008768:Methylmethacrylates / Q000737:chemistry; D008854:Microscopy, Electron; D008956:Models, Chemical; D010084:Oxidation-Reduction; D011108:Polymers; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011239:Prednisolone / Q000008:administration & dosage* / Q000494:pharmacology; D013256:Steroids / Q000008:administration & dosage*; D013696:Temperature; D013778:Tetrazolium Salts / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D013997:Time Factors
chemical_list: D001672:Biocompatible Materials; D004396:Coloring Agents; D004337:Drug Carriers; D005938:Glucocorticoids; D008768:Methylmethacrylates; D011108:Polymers; D013256:Steroids; D013778:Tetrazolium Salts; D013844:Thiazoles; D019904:Polymethyl Methacrylate; D011239:Prednisolone; C022616:thiazolyl blue; D001585:Benzoyl Peroxide