Purpose: To characterize the concentration-time profile of triamcinolone acetonide (TA) in human aqueous after a single, 20-mg, intravitreal injection.
Design: Case series.
Participants: Seven patients and 10 eyes that received intravitreal injection of the decanted 20 mg of TA.
Methods: Fifty microliters of aqueous were sampled from each intravitreally TA-injected eye at postinjection monthly interval and the samples were subjected to liquid chromatography coupled with tandem mass spectrometric detection for TA.
Main outcome measures: The TA concentration in the aqueous.
Results: The TA was cleared from the aqueous in a monoexponential manner with a half-life of 29.6 days and clearance coefficient of 0.0234 (1/day). The extrapolated maximum TA concentration in aqueous was about 3312 ng/ml and the area under the curve was 74,017 day x ng/ml.
Conclusions: The TA concentration in human aqueous could stay above therapeutic concentration for 150 days (5 half-lives with remaining TA concentration of 104 ng/ml) after a 20-mg intravitreal injection, suggesting an even longer therapeutic concentration of TA in vitreous.