Quantification of sedimented triamcinolone for intravitreal injection.

PURPOSE: To develop a practical method to concentrate triamcinolone acetonide for intravitreal injection. METHODS: A protocol using sedimentation was developed to increase the concentration of triamcinolone acetonide in a 0.1 mL dose. Two variables were investigated: sedimentation time and initial volume of triamcinolone acetonide. Predetermined volumes (0.2 mL to 1 mL) of triamcinolone acetonide were aspirated into tuberculin syringes. Each syringe was placed in a vertical position for a designated time (0 to 120 minutes). The supernatant was then discarded to reduce the volume to 0.1 mL. High-performance liquid chromatography was then used for quantification of the triamcinolone acetonide. RESULTS: The greatest concentrations of triamcinolone acetonide were seen after 120 minutes of sedimentation. At that time point, the 0.2 mL, 0.3 mL, and 0.5 mL initial volumes resulted in, respectively, 7.4 mg +/- 0.8 mg (mean +/- SE), 9.8 mg +/- 0.2 mg, and 16.4 mg +/- 0.7 mg triamcinolone acetonide in 0.1 mL. The 1.0-mL initial volume resulted in 25.7 mg +/- 0.9 mg triamcinolone acetonide in 0.1 mL; this was the maximum concentration achieved in the experiment. CONCLUSION: The authors have developed a simple protocol to use sedimentation to greatly increase the concentration of triamcinolone acetonide, starting from commercially available triamcinolone acetonide up to a maximum of 25.7 mg per 0.1 mL (257 +/- 9 mg/mL). This study demonstrates a practical and quantifiable method to increase triamcinolone concentration for intravitreal injections.

Reproducibility of quantitative optical coherence tomography subanalysis in neovascular age-related macular degeneration.

PURPOSE: To determine the intergrader reproducibility for computer-assisted grading of optical coherence tomography (OCT) images in eyes with neovascular age-related macular degeneration (AMD), by using a standardized grading procedure. METHODS: Sixty OCT image sets (of six radial lines each) were independently analyzed by two graders using validated custom software (OCTOR) to draw boundaries manually on OCT B-scans. Spaces delineated by these boundaries included retina, subretinal fluid, subretinal tissue, and pigment epithelial detachments (PEDs). Volume measurements for the nine Early Treatment of Diabetic Retinopathy Study (ETDRS) subfields and the mean foveal center point (FCP) thickness were calculated by the software and compared by using weighted kappa statistics and intraclass correlation coefficients (ICCs). RESULTS: Intergrader comparison of the foveal central subfield (FCS) volume, total volume, and mean FCP thickness showed a high level of agreement and strong correlation between measurements for all spaces (kappa(weighted) = 0.72-0.97; ICC = 0.92-0.99). The best agreement was observed for total volume of the combination of all four graded spaces (kappa(weighted) = 0.97, mean difference = 0.31 mm(3), or 2.51%). The highest ICCs were seen for FCP thickness measurements. The poorest agreement was found for grading of subretinal tissue. Eyes with advanced choroidal neovascularization (CNV) and poor visibility of the retinal pigment epithelium (RPE) band appeared to show the greatest intergrader discrepancies. CONCLUSIONS: Analysis of OCT images by trained graders using computer-assisted grading software allows for highly reproducible quantitative measurements, even in eyes with complex diseases such as neovascular AMD. Quantitative subanalysis may be useful in studying the differential morphologic effect of therapies on various anatomic components.