title: Intravitreal concentration and clearance of triamcinolone acetonide in nonvitrectomized human eyes.
abstract: OBJECTIVE
  To determine the intravitreal concentration and clearance of triamcinolone acetonide at various intervals after intravitreal injection into nonvitrectomized eyes.
  
  
  METHODS
  Six participants were administered 4 mg (0.1 cc) of triamcinolone acetonide ophthalmic suspension. All six eyes underwent therapeutic pars plana vitrectomy with membranectomy at various post injection intervals ranging from 1.25 to 5 months from the intravitreal injection. Undiluted specimens of vitreous overlying the macula and of aqueous humor were submitted for analysis. Vitreous and aqueous humor concentrations of triamcinolone were measured by high performance liquid chromatography.
  
  
  RESULTS
  Four eyes demonstrated detectable intravitreal concentrations of triamcinolone acetonide between 1.25 and 2.75 months after a single injection. Two eyes had an undetectable level of triamcinolone in both the vitreous and aqueous at 3 and 5 months post single injection.
  
  
  CONCLUSIONS
  The intravitreal concentration of triamcinolone acetonide is detectable up to 2.75 months post a single 4 mg injection in nonvitrectomized eyes. A reinjection interval of 3 months may be needed to achieve sustained measurable levels of triamcinolone in nonvitrectomized patients.
authors.affiliation: Retina Consultants of Alabama, P.C., Department of Ophthalmology, Callahan Eye Foundation Hospital, University of Alabama at Birmingham, USA.
authors.forename: John O
authors.initials: JO
authors.lastname: Mason
authors.forename: Mamta D
authors.initials: MD
authors.lastname: Somaiya
authors.forename: Ravinder J
authors.initials: RJ
authors.lastname: Singh
mesh_terms: D000368:Aged; D001082:Aqueous Humor / Q000378:metabolism; D001682:Biological Availability; D005260:Female; D005938:Glucocorticoids / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D014222:Triamcinolone Acetonide / Q000493:pharmacokinetics*; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism*
chemical_list: D005938:Glucocorticoids; D014222:Triamcinolone Acetonide