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I. Kreissig, U.H. M. Spandau, P. Schmitz–Valckenberg, K. Stiefvater, J.B. Jonas; Comparison of Triamcinolone Acetonide Dosages of Prepared Crystal Suspensions: Filtered and Unfiltered . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4731.
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Purpose: To determine dosage of triamcinolone acetonide (TA) and possible remainder of benzyl alcohol (solvent) after filtration and washings of TA crystals, as done at 2 different pharmacy departments. Methods: 23 TA samples were prepared by hospital pharmacy in Koblenz/Germany and Mannheim/Germany. In Koblenz 20 TA samples were prepared: 10 samples with 25 mg TA of which 5 were unfiltered and 5 filtered, and 10 samples with 4 mg TA of which 5 were unfiltered and 5 filtered. In Mannheim 3 samples with 25mg TA were prepared and filtered. Preparation was done as follows: For an intended dosage of 25mg TA, 0.625 ml TA suspension were withdrawn from the Volon A 40mg ampula (analog to Kenalog 40mg); for an intended dosage of 4mg TA, 0.1 ml of TA suspension were withdrawn and the content of syringe pushed through millipore filter (5 micrometer), after that crystals were washed 3 times with 0.9% NaCl solution. Using High Phase Liquid Chromatography (HPLC) with a sensitivity of 0.1mg/l, the concentration of TA crystals and solved TA were determined and tested for residual benzyl alcohol Results: In Koblenz–pharmacy: Of the 10 samples with intended 25mg TA, the 5 unfiltered contained 23.4±2.3mg TA and the 5 after filtration and washings of crystals 12.8 ± 0.7mg TA; of the 10 samples with intended 4mg TA, the 5 unfiltered contained 3.1 ± 0.6mg TA, the 5 after filtration and washings 2.4 ± 0.8mg TA. In Mannheim–pharmacy: The 3 samples with intended 25mg TA contained after filtration and washings 23.8 ± 0.6mg TA with a mean concentration of 0.0013 ± 0.0001mg/0.1ml benzyl alcohol. Conclusions: The intended dosage of TA for an intravitreal injection is less after filtration and washings of the crystals, as done for removing the solvent, benzyl alcohol. The variations in the resulting TA dosage differs significantly between pharmacy departments, however, it is minor within the same pharmacy. The intended TA dosage for intravitreal injection, filtered or unfiltered, is less when determined by HPLC. Future efforts are needed to provide for prepared TA standardized dosages for the clinician and future randomized studies.
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