title: [The dynamic study of retinoic acid and its alginate sodium microspheres in rabbit eye].
abstract: OBJECTIVE
  To obtain a intravitreous delay release system by injection of biodegradable polymers (alginate sodium-retinoic acid microspheres, AGS-RA microspheres) to the rabbit vitreous and study the release character of RA delivery system in vitro.
  
  
  METHODS
  RA was mixed with 1.5% alginate sodium and microspheres was made by a special electrostatic generator after dissolved in organic solvent; The content of AGS-RA in the microspheres and its release from the microspheres were measured by spectrophotometer. The characteristic of the metabolic dynamics of AGS-RA in the microspheres was analyzed by HPLC.
  
  
  RESULTS
  The size of microspheres we manufacture is (95.2443 +/- 8.6265) microm; Medicine contain quantity of RA is (1.7644 +/- 0.0453) microg/mg; Vitro test show that RA in the microspheres is release evenly in the 28 days of observation; Inject medicine to vitreous cavity show no poisonous side effect; The medicine dynamics research of microspheres showed that medicine is being even in 6 weeks releasing [the aqueous RA density of 1, 3 d, 1, 2, 3, 4, 5, 6 weeks is (23.79 +/- 0.15), (33.45 +/- 0.48), (19.95 +/- 0.79), (21.12 +/- 0.47), (19.65 +/- 0.35), (20.01 +/- 0.25), (18.24 +/- 0.27), (18.5 +/- 0.68) ng/ml, respectively]. Just in the 3rd day there is a release summit.
  
  
  CONCLUSIONS
  In vivo and in vitro tests show that AGS-RA microspheres can delay RA release uniformity.
authors.affiliation: Department of Ophthalmology, General Hospital of the PLA, Beijing 100853, China. wangfxiang@263.net
authors.forename: Feng-xiang
authors.initials: FX
authors.lastname: Wang
authors.forename: Shou-zhi
authors.initials: SZ
authors.lastname: He
authors.forename: Xin-jian
authors.initials: XJ
authors.lastname: Li
authors.forename: Qiu-li
authors.initials: QL
authors.lastname: Liang
authors.forename: Bing
authors.initials: B
authors.lastname: Chen
mesh_terms: D000464:Alginates / Q000493:pharmacokinetics*; D000818:Animals; D001082:Aqueous Humor / Q000378:metabolism*; D003692:Delayed-Action Preparations; D005260:Female; D020723:Glucuronic Acid / Q000493:pharmacokinetics; D006603:Hexuronic Acids / Q000493:pharmacokinetics; D008297:Male; D008863:Microspheres; D011817:Rabbits; D014212:Tretinoin / Q000493:pharmacokinetics*; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D000464:Alginates; D003692:Delayed-Action Preparations; D006603:Hexuronic Acids; D014212:Tretinoin; D020723:Glucuronic Acid