title: Intraocular concentration of triamcinolone acetonide after intravitreal injection in the rabbit eye.
abstract: OBJECTIVE
  To examine the decrease in the intraocular concentration of intravitreally injected triamcinolone acetonide over an 8-month period in a rabbit model.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  The study included 18 white New Zealand rabbits.
  
  
  METHODS
  The animals received an intravitreal injection of 6 mg triamcinolone acetonide. Vitreous and aqueous humor samples of the anterior and posterior chamber were taken at the first and third day, at 1 and 2 weeks, and at 1, 1.5, 2, 3, 6, and 8 months. The concentrations of triamcinolone were analyzed using a high-phase liquid chromatography assay.
  
  
  METHODS
  Intraocular concentration of triamcinolone during follow-up.
  
  
  RESULTS
  Over the entire study period, triamcinolone concentrations were significantly higher in the vitreous samples than in the anterior chamber samples (day 1, 14 434+/-10 768 microg/l vs. 21.0+/-18.9 microg/l; day 30, 571.3+/-329.6 microg/l vs. 6.1+/-1.6 microg/l; month 8, 70.7+/-37.0 microg/l vs. 3.3+/-1.6 microg/l). In the anterior chamber, the triamcinolone concentrations were highest at 3 days after the injection (28.9+/-24.5 microg/l), and in the vitreous, the concentrations were highest at the first day (14,434.0+/-10,768 microg/l). Triamcinolone levels in the vitreous and in the anterior chamber followed a 2-compartment model, with an exponential decrease in the concentration within the first 4 weeks, followed by a steady decline over the following months. At 8 months, the triamcinolone concentrations were 70.7+/-37.0 microg/l in the vitreous samples and 3.3+/-1.6 microg/l in the anterior chamber samples.
  
  
  CONCLUSIONS
  The decrease in the concentration of triamcinolone after an intravitreal injection of 6 mg in rabbits follows a 2-compartment model, with an exponential decrease in the first 4 weeks followed by a more linear decrease. During the entire study period, the triamcinolone concentration was significantly higher in the vitreous than in the anterior chamber. After a single intravitreal triamcinolone injection of 6 mg in rabbits, triamcinolone is detectable for at least 8 months after the injection.
authors: Department of Ophthalmology, Faculty of Clinical Medicine Mannheim of the University Heidelberg, Heidelberg, Germany. bernd_kamppeter@t-online.de
authors: Bernd A
authors: BA
authors: Kamppeter
authors: Ali
authors: A
authors: Cej
authors: Jost B
authors: JB
authors: Jonas
mesh_terms: D000818:Animals; D001082:Aqueous Humor / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000008:administration & dosage / Q000493:pharmacokinetics*; D007267:Injections; D011817:Rabbits; D014222:Triamcinolone Acetonide / Q000008:administration & dosage / Q000493:pharmacokinetics*; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D005938:Glucocorticoids; D014222:Triamcinolone Acetonide