@article {1364500,
	title = {Pharmacokinetic study of vitreous and serum concentrations of triamcinolone acetonide after posterior sub-tenon{\textquoteright}s injection},
	journal = {Am J Ophthalmol},
	volume = {153},
	number = {5},
	year = {2012},
	month = {2012 May},
	pages = {939-48},
	abstract = {PURPOSE: To compare a theoretical pharmacokinetic model of triamcinolone acetonide after posterior sub-Tenon{\textquoteright}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{\textquoteright}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{\textquoteright}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{\textquoteright}s triamcinolone.},
	keywords = {Biological Availability, Chromatography, High Pressure Liquid, Computer Simulation, Glucocorticoids, Humans, Hydrocortisone, Injections, Intraocular, Mass Spectrometry, Models, Theoretical, Tenon Capsule, Triamcinolone Acetonide, Vitrectomy, Vitreous Body},
	issn = {1879-1891},
	doi = {10.1016/j.ajo.2011.10.021},
	author = {Kovacs, Kyle and Wagley, Sushant and Quirk, Matthew T and Ceron, Olga M and Silva, Paolo A and Singh, Ravinder J and Gukasyan, Hovhannes J and Arroyo, Jorge G}
}
