title: Feasibility of drug targeting to the retinal pigment epithelium with biodegradable microspheres.
abstract: There are several systems of delivering drugs to cells with phagocytic activity. We studied the possibility of targeting drugs to retinal pigment epithelial (RPE) cells with the use of surface-modified microspheres. A fluorescent dye, 1,4-bis[2-(5-phenyloxazolyl)]-benzene (POPOP), was incorporated into microspheres of poly(lactic acid) for use as a marker to evaluate drug delivery. Phagocytosis of the microspheres, with or without gelatin precoating, was carried out at 37 degrees C and 4 degrees C. The cell-incorporated fluorescence of POPOP was measured, and scanning electron microscopy was used to confirm phagocytosis. At 4 degrees C, no uptake of POPOP was noted; however at 37 degrees C, cell-associated fluorescence was observed to increase for up to 24 hr. In comparison with bare microspheres, gelatin precoating significantly enhanced phagocytosis (P < 0.001) at the same incubation times. These results suggested that drug delivery to RPE cells may be feasible by means of surface-modified polymer microspheres.
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, Kyoto University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Moritera
authors.forename: Y
authors.initials: Y
authors.lastname: Ogura
authors.forename: N
authors.initials: N
authors.lastname: Yoshimura
authors.forename: S
authors.initials: S
authors.lastname: Kuriyama
authors.forename: Y
authors.initials: Y
authors.lastname: Honda
authors.forename: Y
authors.initials: Y
authors.lastname: Tabata
authors.forename: Y
authors.initials: Y
authors.lastname: Ikada
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D002478:Cells, Cultured; D016503:Drug Delivery Systems; D005240:Feasibility Studies; D005333:Fetus; D005780:Gelatin; D006801:Humans; D017737:Macrophages, Peritoneal / Q000502:physiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008863:Microspheres; D010587:Phagocytosis / Q000502:physiology; D010857:Pigment Epithelium of Eye / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D005780:Gelatin