%0 Journal Article %J Am J Ophthalmol %D 2012 %T Pharmacokinetic study of vitreous and serum concentrations of triamcinolone acetonide after posterior sub-tenon's injection %A Kovacs, Kyle %A Wagley, Sushant %A Quirk, Matthew T %A Ceron, Olga M %A Silva, Paolo A %A Singh, Ravinder J %A Gukasyan, Hovhannes J %A Arroyo, Jorge G %K Biological Availability %K Chromatography, High Pressure Liquid %K Computer Simulation %K Glucocorticoids %K Humans %K Hydrocortisone %K Injections, Intraocular %K Mass Spectrometry %K Models, Theoretical %K Tenon Capsule %K Triamcinolone Acetonide %K Vitrectomy %K Vitreous Body %X PURPOSE: To compare a theoretical pharmacokinetic model of triamcinolone acetonide after posterior sub-Tenon's injection with experimental serum and undiluted vitreous triamcinolone acetonide concentrations obtained during pars plana vitrectomy. DESIGN: Clinical-practice, prospective, interventional case series study. METHODS: This study compared computer-modeled triamcinolone acetonide diffusion after posterior sub-Tenon's injection with triamcinolone acetonide levels in experimental undiluted vitreous and serum samples from 57 patients undergoing vitrectomy assessed via mass spectrometry and high-pressure liquid chromatography. At least 5 pairs of samples were collected at each of 7 time points (1 day, 3 days, and 1, 2, 3, 4, and 8 weeks) after triamcinolone acetonide injection, with 6 controls without injection. Cortisol levels were measured in 31 sets of samples. RESULTS: The theoretical model predicted that triamcinolone acetonide levels in systemic blood, vitreous, and choroidal extracellular matrix would plateau after 3 days at 15 ng/mL, 227 ng/mL and 2230 ng/mL, respectively. Experimental vitreous levels of triamcinolone peaked at 111 ng/mL at day 1, then reached a plateau in the range 15 to 25 ng/mL, while serum triamcinolone levels peaked at day 3 near 35 ng/mL and plateaued near 2 to 8 ng/mL. Serum triamcinolone and cortisol levels were inversely correlated (Spearman -0.42, P = .02). CONCLUSIONS: The theoretical model predicts efficient delivery of triamcinolone acetonide from the posterior sub-Tenon's space to the extracellular choroidal matrix. The experimental findings demonstrate low levels of serum triamcinolone that alter systemic cortisol levels and higher vitreous levels lasting at least 1 month. Both assessments support trans-scleral delivery of posterior sub-Tenon's triamcinolone. %B Am J Ophthalmol %V 153 %P 939-48 %8 2012 May %G eng %N 5 %1 http://www.ncbi.nlm.nih.gov/pubmed/22310078?dopt=Abstract %R 10.1016/j.ajo.2011.10.021