title: Biodegradable scleral implant for controlled intraocular delivery of betamethasone phosphate.
abstract: We evaluated nail-like, biodegradable scleral implants as a controlled intraocular delivery system of betamethasone phosphate (BP) for the treatment of chronic uveitis using pigmented rabbits. The scleral implants, which contained 10% and 25% of BP (weight 8.5 mg; length 5 mm), were made of poly (D,L-lactide-co-glycolide) (PLGA). In vivo release and retinal toxicity after implantation were also studied in pigmented rabbits. The in vitro release studies demonstrated the 10% and 25% BP-loaded scleral implants released BP in a biphasic release pattern for at least 1 month. The BP concentrations in the vitreous and the retina/choroid after application of scleral implants in pigmented rabbit eyes stayed within the concentration range capable of suppressing inflammatory responses for over 1 month. The BP concentration was greater in the retina/choroid than in the vitreous throughout the study. No substantial toxic reactions in the retina were observed by electroretinography. Our findings suggest that the BP-loaded scleral implant may be a promising device for treatment of chronic uveitis.
authors.affiliation: Department of Ophthalmology, Nagoya City University Medical School, Mizuho-ku, Nagoya 467-0001, Japan. kuno@iwa.att.ne.jp
authors.forename: N
authors.initials: N
authors.lastname: Kunou
authors.forename: Y
authors.initials: Y
authors.lastname: Ogura
authors.forename: Y
authors.initials: Y
authors.lastname: Honda
authors.forename: S H
authors.initials: SH
authors.lastname: Hyon
authors.forename: Y
authors.initials: Y
authors.lastname: Ikada
mesh_terms: D000818:Animals; D001623:Betamethasone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000633:toxicity; D001672:Biocompatible Materials; D001673:Biodegradation, Environmental; D002908:Chronic Disease; D016503:Drug Delivery Systems; D004343:Drug Implants; D004596:Electroretinography; D005123:Eye / Q000187:drug effects / Q000378:metabolism; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000633:toxicity; D066298:In Vitro Techniques; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011817:Rabbits; D012590:Sclera; D014605:Uveitis / Q000188:drug therapy
chemical_list: D001672:Biocompatible Materials; D004343:Drug Implants; D005938:Glucocorticoids; C028994:betamethasone sodium phosphate; D001623:Betamethasone