title: Design and evaluation of a liposomal delivery system targeting the posterior segment of the eye.
abstract: The purpose of this study was to evaluate the potential of submicron-sized liposomes (ssLips) as a novel system for delivering ocular drugs to the eye's posterior segment. Fluorescence emission of coumarin-6 formulated into ssLip was obvious in that segment in mice after eyedrop administration of the liposomal suspension. Such fluorescence was not observed after administration of either multilamellar vesicles or dimethyl sulfoxide (DMSO) solution containing the same amount of coumarin-6. The highest fluorescence of ssLip occurred 30 min after eyedrop administration, and all fluorescence disappeared after 180 min. The ssLip based on l-alpha-distearoyl phosphatidylcholine (DSPC ssLip) showed higher fluorescence emission in the retina than that based on egg phosphatidylcholine (EPC ssLip). These results confirmed that the magnitude of fluorescence in the retina was closely related to both liposome rigidity and particle size. Images of the entire eye showed that ssLip was delivered via the non-corneal pathway after administration. The liposomes tested in ocular cells showed little cytotoxicity. These results suggest that ssLip can be used to deliver drugs to the posterior segment of the eye.
authors.affiliation: Laboratory of Pharmaceutical Engineering, Gifu Pharmaceutical University, Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Hironaka
authors.forename: Yuta
authors.initials: Y
authors.lastname: Inokuchi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Tozuka
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Shimazawa
authors.forename: Hideaki
authors.initials: H
authors.lastname: Hara
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Takeuchi
mesh_terms: D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002645:Chickens; D003228:Conjunctiva / Q000166:cytology; D003315:Cornea / Q000166:cytology; D003374:Coumarins; D005123:Eye / Q000378:metabolism; D005456:Fluorescent Dyes; D006801:Humans; D008081:Liposomes / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics* / Q000633:toxicity*; D008297:Male; D051379:Mice; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence; D009883:Ophthalmic Solutions / Q000008:administration & dosage; D010063:Ovum / Q000737:chemistry; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry*; D012160:Retina / Q000378:metabolism*; D013844:Thiazoles
chemical_list: D003374:Coumarins; D005456:Fluorescent Dyes; D008081:Liposomes; D009883:Ophthalmic Solutions; D010713:Phosphatidylcholines; D013844:Thiazoles; C517282:coumarin 6; C010942:1,2-distearoyllecithin