Intraocular irrigating
solution containing 1 µg/mL
adrenaline is widely used during
cataract surgery to maintain pupil dilation. Prepared intraocular irrigating solutions are recommended for use within 6 h. After the irrigating
solution is admistered for dilution, the
adrenaline may become oxidized, and this may result in a decrease in its biological activity. However, the stability of
adrenaline in intraocular irrigating
solution is not fully understood. The aim of this study was to evaluate the stability of
adrenaline in clinically used irrigating solutions of varying pH. Six hours after mixing, the
adrenaline percentages remaining were 90.6%±3.7 (pH 7.2), 91.1%±2.2 (pH 7.5), and 65.2%±2.8 (pH 8.0) of the initial concentration. One hour after mixing, the percentages remaining were 97.6%±2.0 (pH 7.2), 97.4%±2.7 (pH 7.5), and 95.6%±3.3 (pH 8.0). The degradation was especially remarkable and time dependent in the
solution at pH 8.0. These results indicate that the concentration of
adrenaline is decreased after preparation. Moreover, we investigated the influence of
sodium bisulfite on
adrenaline stability in irrigating
solution. The percentage
adrenaline remaining at 6 h after mixing in irrigating
solution (pH 8.0) containing
sodium bisulfite at 0.5 µg/mL (concentration in irrigating
solution) or at 500 µg/mL (concentration in the undiluted
adrenaline preparation) were 57.5 and 97.3%, respectively. Therefore, the low concentration of
sodium bisulfite in the irrigating
solution may be a cause of the
adrenaline loss. In conclusion, intraocular irrigation
solution with
adrenaline should be prepared just prior to its use in surgery.