PMID- 14691179
OWN - NLM
STAT- MEDLINE
DCOM- 20040120
LR  - 20190607
IS  - 0146-0404 (Print)
IS  - 0146-0404 (Linking)
VI  - 45
IP  - 1
DP  - 2004 Jan
TI  - Feasibility of drug delivery to the posterior pole of the rabbit eye with an 
      episcleral implant.
PG  - 238-44
AB  - PURPOSE: To evaluate the feasibility of a nonbiodegradable polymeric episcleral 
      implant as a new controlled intraocular delivery system of betamethasone (BM) to 
      the posterior pole of the eye. METHODS: The episcleral implant, which is composed 
      of a drug-releasing component and a suture tag, released BM through an ethylene 
      vinyl acetate membrane. The implants were placed on the sclera in 12 eyes of 12 
      Japanese white rabbits so that the drug-releasing surface could attach to the 
      sclera at the posterior pole. BM concentrations in the aqueous humor, vitreous, 
      and retina-choroid (posterior half and anterior half) were determined by 
      high-performance liquid chromatography (HPLC) at weeks 1, 2, and 4 after 
      implantation. In addition, the intraocular tissue distribution of the drug was 
      evaluated by fluorescein microscopy after implantation of the implant loaded with 
      6-carboxy fluorescein diacetate (6-CFDA) as a drug marker. Retinal toxicity was 
      evaluated by electroretinography and histologic examination. RESULTS: The implant 
      showed zero-order release profiles both in vitro and in vivo for 4 weeks. BM 
      concentrations in the retina-choroid after implantation were maintained above the 
      concentrations effective for suppressing inflammatory reactions for at least 4 
      weeks. The BM concentration was greater in the posterior half of the 
      retina-choroid than in the vitreous. It was confirmed that 6-CFDA penetrated 
      through the sclera and dispersed into the retina-choroid. Fluorescence from 
      6-CFDA gradually decreased in intensity with increased distance from the 
      implantation site. Electroretinography and histologic study showed no substantial 
      toxic reactions. CONCLUSIONS: These findings suggest that the episcleral implant 
      may be a useful drug carrier for intraocular delivery of BM, especially for the 
      posterior part of the eye.
FAU - Kato, Aki
AU  - Kato A
AD  - Department of Ophthalmology, Nagoya City University Medical School, Nagoya, 
      Japan.
FAU - Kimura, Hideya
AU  - Kimura H
FAU - Okabe, Komei
AU  - Okabe K
FAU - Okabe, Junko
AU  - Okabe J
FAU - Kunou, Noriyuki
AU  - Kunou N
FAU - Ogura, Yuichiro
AU  - Ogura Y
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Invest Ophthalmol Vis Sci
JT  - Investigative ophthalmology & visual science
JID - 7703701
RN  - 0 (Biocompatible Materials)
RN  - 0 (Drug Implants)
RN  - 0 (Fluoresceins)
RN  - 0 (Glucocorticoids)
RN  - 3348-03-6 (6-carboxyfluorescein diacetate)
RN  - 9842X06Q6M (Betamethasone)
SB  - IM
MH  - Animals
MH  - Aqueous Humor/drug effects/metabolism
MH  - Betamethasone/*administration & dosage/pharmacokinetics/toxicity
MH  - Biocompatible Materials
MH  - Biological Availability
MH  - Choroid/drug effects/metabolism
MH  - Chromatography, High Pressure Liquid
MH  - *Drug Delivery Systems
MH  - Drug Implants
MH  - Electroretinography
MH  - Feasibility Studies
MH  - Fluoresceins
MH  - Glucocorticoids/*administration & dosage/pharmacokinetics/toxicity
MH  - Microscopy, Fluorescence
MH  - Rabbits
MH  - Retina/drug effects/metabolism
MH  - Sclera/*drug effects/metabolism
MH  - Vitreous Body/drug effects/metabolism
EDAT- 2003/12/24 05:00
MHDA- 2004/01/21 05:00
CRDT- 2003/12/24 05:00
PHST- 2003/12/24 05:00 [pubmed]
PHST- 2004/01/21 05:00 [medline]
PHST- 2003/12/24 05:00 [entrez]
AID - 10.1167/iovs.02-1258 [doi]
PST - ppublish
SO  - Invest Ophthalmol Vis Sci. 2004 Jan;45(1):238-44. doi: 10.1167/iovs.02-1258.