Document resource
Background and Importance Fluorescein sodium ophthalmic strips are sterile paper strips infused with fluorescein sodium dye, used by healthcare professionals to evaluate corneal abrasions and tear film stability, and to measure intraocular pressure. Since fluorescein sodium ophthalmic strips are not commercially available in our market, they must be prepared in the hospital pharmacy unit. However, the method of preparation and the quantity of released fluorescein sodium are not yet standardised.Aim and Objectives To standardise the method of preparation of fluorescein sodium ophthalmic strips by comparing the differences in the amount of released fluorescein sodium related to the impregnated surface area.Material and Methods One edge of each paper strip is dipped into 10% sterile fluorescein sodium solution, prepared by dissolving fluorescein sodium into sterile water for injection and autoclaved. The paper strips are further air-dried for about 15 minutes in a laminar-flow hood. Using this method, strips with four different fluorescein-impregnated surface areas (15 mm 2, 25 mm2, 35 mm2, and 50 mm2) were prepared. The quantity of fluorescein sodium extracted from the strips in aqueous solution was determined spectrophotometrically at 492 nm.Results We established a direct correlation between the quantity of fluorescein sodium and the impregnated surface area, as the amounts of fluorescein sodium extracted from the strips with surface area of 15 mm 2, 25 mm2, 35 mm2 and 50 mm2 were 235 μg, 366 μg, 617 μg and 1100 μg, respectively. In relation to the standardised amount of fluorescein sodium of 300 μg, the percentages of fluorescein sodium released from the strips of surface area of 15 mm2, 25 mm2, 35 mm2 and 50 mm2 were 78%, 122%, 206% and 367%, respectively. Therefore, only the amount of fluorescein sodium released from the strip of 25 mm2 met the requirements of USP-NF 2025 monography (100-160% of the labelled amount of fluorescein sodium).Conclusion and Relevance Modification of the impregnated surface area provides the possibility of achieving the desirable amount of released fluorescein sodium, thus reducing excessive dye use and waste, as well as ensuring reliable and consistent results. These results could lead to the optimal use of fluorescein sodium ophthalmic strips for diagnostic purposes and consequently improve patient outcomes.Conflict of Interest No conflict of interest