title: Pharmacokinetics and retinal toxicity of various doses of intravitreal triamcinolone acetonide in rabbits.
abstract: OBJECTIVE
  To compare the pharmacokinetics and retinal toxicity of various doses of intravitreal triamcinolone acetonide (TA) in rabbits.
  
  
  METHODS
  The rabbits received intravitreal injections of 4 mg and 8 mg TA. The drug concentrations were determined with high-performance liquid chromatography after extraction from the vitreous at various time points. The main pharmacokinetics parameters were calculated with 3p97 pharmacokinetics software. The intraocular pressure, electroretinography, and pathological examinations were evaluated before and after intravitreal injection of different doses of TA.
  
  
  RESULTS
  The half-life of intravitreal injection of 4 mg and 8 mg TA was 24 days and 34 days, respectively. No significant differences were found in intraocular pressure (p>0.05) and the electroretinography b-wave amplitudes (p>0.05) among the rabbits before and after intravitreal injection of 4 mg and 8 mg TA. Light and electron microscopy did not show any retinal damage in any group.
  
  
  CONCLUSIONS
  Intravitreal injection of 4 mg and 8 mg TA are safe for the rabbit retina. The injection of 8 mg TA produced a longer vitreous half-life and had a prolonged effect on the retina. This conclusion may be referenced in the clinical application of TA in retinal diseases.
authors.affiliation: Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: You-Fan
authors.initials: YF
authors.lastname: Ye
authors.affiliation: Henan Eye Institute, Henan Eye Hospital, Zhengzhou, China.
authors.forename: Yong-Feng
authors.initials: YF
authors.lastname: Gao
authors.affiliation: Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Hua-Tao
authors.initials: HT
authors.lastname: Xie
authors.affiliation: Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Hai-Jun
authors.initials: HJ
authors.lastname: Wang
mesh_terms: D000818:Animals; D004596:Electroretinography; D005260:Female; D005654:Fundus Oculi; D007429:Intraocular Pressure / Q000187:drug effects; D058449:Intravitreal Injections; D008297:Male; D011817:Rabbits; D012160:Retina / Q000187:drug effects* / Q000473:pathology* / Q000503:physiopathology / Q000648:ultrastructure; D013997:Time Factors; D014222:Triamcinolone Acetonide / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000633:toxicity*
chemical_list: D014222:Triamcinolone Acetonide