title: In vitro and in vivo evaluation of an ocular delivery system of 5-fluorouracil microspheres.
abstract: Solvent evaporation technique with O/O (oil/oil) emulsion was used to prepare 5-FU (5-fluorouracil) biodegradable microspheres with a polymer of poly(dl-lactide-co-glycolide) combining lecithin as an emulsifier. In vitro drug release was conducted in phosphate buffer with pH 7.4 at 37 degrees C. For in vivo studies, 10 mg of 5-FU microspheres (containing 1 mg of 5-FU) were implanted in the conjunctival area of the rabbit eye. Rabbits were sacrificed at certain time intervals within 7 days after drug application. Samples of aqueous humor and sclera were prepared and analyzed by the high performance liquid chromatography (HPLC) method. The tested 5-FU microsphere contained 10% drug with a mean particle size of 4.4 +/- 0.6 microm. The microsphere had a burst release initially (64.9 +/- 1.5%), followed by a sustained release; the cumulative release at time points of 1, 10 and 21 days were 71.9 +/- 1.9%, 80.1 +/- 2.1% and 89.8 +/- 2.3%, respectively. For in vivo studies, aqueous humor levels showed a peak at the first sampling point (2 hr), then maintained low levels of 5-FU with a range 0.2-1 microg/mL. Scleral levels were 20-80 microg/mL during a 7-day study. Our results indicate that the prepared 5-FU microsphere provided a long-term release for more than 1 week. The preparation showed no irritation and low toxicity (< 100 microg/mL). For application to the eye, it might be potentially useful as a complement drug system in glaucoma filtration surgery.
authors.affiliation: School of Pharmacy, National Defense Medical Center, Taipei, Taiwan, Republic of China. cch@ndmctsgh.edu.tw
authors.forename: C H
authors.initials: CH
authors.lastname: Chiang
authors.forename: S M
authors.initials: SM
authors.lastname: Tung
authors.forename: D W
authors.initials: DW
authors.lastname: Lu
authors.forename: M K
authors.initials: MK
authors.lastname: Yeh
mesh_terms: D000818:Animals; D001082:Aqueous Humor / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004337:Drug Carriers; D004343:Drug Implants; D005260:Female; D018463:Filtering Surgery; D005472:Fluorouracil / Q000008:administration & dosage* / Q000493:pharmacokinetics; D066298:In Vitro Techniques; D019344:Lactic Acid; D008297:Male; D008863:Microspheres; D010316:Particle Size; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D011817:Rabbits; D012590:Sclera / Q000737:chemistry
chemical_list: D004337:Drug Carriers; D004343:Drug Implants; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D005472:Fluorouracil