title: Characterisation of systemic and ocular drug level of triamcinolone acetonide following a single sub-Tenon injection.
abstract: AIM To characterise the pharmacokinetics of triamcinolone acetonide (TA) in various ocular tissues following a single sub-Tenon injection. METHODS Twenty-one Chinchilla adult pigmented rabbits received sub-Tenon injection of TA (40 mg in 0.4 ml) in their right eyes. Three animals were killed at each designated time points (3 h, 1 day, 3 days, 7 days, 14 days, 21 days and 30 days) and the globes were snap frozen and dissected into aqueous, iris-ciliary body, vitreous, neuroretina and retinal pigment epithelium (RPE)/choroid. The concentrations of TA in the various ocular tissues were analysed using ultra-performance liquid chromatography, coupled with tandem mass spectrometric detection. RESULTS TA concentration followed a mono-exponential decrease over the study period in all ocular tissues of the injected eyes. The concentration was much higher in the RPE/choroid (892.14+/-558.11 ng/g at post-injection day 30) than in the other tissues (171.65+/-136.40 ng/g in neuroretina, 15.65+/-23.06 ng/ml in vitreous, 3.76+/-1.79 ng/g in iris-ciliary body, 2.64+/-0.96 ng/ml in aqueous at post-injection day 30). The TA level in the RPE/choroid had the lowest coefficient of logarithmic regression (0.07 in RPE/choroid, 0.10 in neuroretina, 0.11 in vitreous, 0.17 in iris-ciliary body, 0.18 in aqueous), indicating a 2.6 times slower clearance than in aqueous. The half-life of TA was 10.4 days in RPE/choroid. TA was detectable in the fellow eyes and was also detectable at very low levels in all blood samples during the entire study period. CONCLUSION TA was mostly cleared from RPE/choroid and retina in a mono-exponential mode. TA was above the therapeutic level for at least 30 days following a sub-Tenon injection.
authors.affiliation: Institute of Ocular Pharmacology, School of Ophthalmology and Optometry, Wenzhou Medical College, 270 Xueyuan Road, Wenzhou, Zhejiang 325027, China.
authors.forename: Kaihui
authors.initials: K
authors.lastname: Nan
authors.forename: Shumao
authors.initials: S
authors.lastname: Sun
authors.forename: Yuli
authors.initials: Y
authors.lastname: Li
authors.forename: Jia
authors.initials: J
authors.lastname: Qu
authors.forename: Guoxing
authors.initials: G
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Luo
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Lingyun
authors.initials: L
authors.lastname: Cheng
mesh_terms: D000818:Animals; D005123:Eye / Q000378:metabolism*; D005938:Glucocorticoids / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D006207:Half-Life; D056965:Injections, Intraocular; D011817:Rabbits; D014222:Triamcinolone Acetonide / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D005938:Glucocorticoids; D014222:Triamcinolone Acetonide