Article
Photostability and safety aspects of Brilliant Blue G and Trypan Blue
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Published: | May 30, 2012 |
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Purpose: To study photostability and toxicity of Brilliant Blue G (BBG), Trypan Blue (TB), and of a combination product (BBG+TB+PEG, polyethylene glycol) applying illumination parameters used in macular surgery.
Methods: BBG 0.25% and TB 0.06% solutions were illuminated with a 300-W xenon surgical light source set on full power for 5 and 60 min and a standard fiberoptic endoillumination probe. Light induced changes of BBG and TB were analysed with high-performance liquid chromatography (HPLC). Generation of singlet oxygen during and after illumination of the solutions was detected using time resolved luminescence spectroscopy at 1270 nm. Cell viability of human ARPE-19 cell culture after incubation with BBG, TB, and BBG+TB+PEG solutions with and without illumination with the same light source was tested with MTT- and trypan blue assays.
Results: The HPLC peak pattern of BBG remained unchanged after short and prolonged illumination. Both solutions are pharmaceutically impure. The HPLC pattern of TB showed a marked increase of several decomposition products with increasing illumination time. Singlet oxygen was not detected during or after illumination of BBG or TB. Incubation with BBG, TB, or BBG+TB+PEG with or without illumination did not alter cell viability.
Conclusion: BBG is a photostable compound while TB decomposes under illumination. Although both BBG and TB appear to be safe in cell culture the epiretinal application of TB is critical because decomposition products may cause yet undetermined toxic effects. The safety profile of BBG and TB could possibly be improved by purification of the solutions.