Photostability of Symphatomimetic Agents in Commonly Used Infusion Media in the Absence and Presence of Bisulfite

Abstract

Previous studies have indicated that epinephrine is photodegraded in sulfite-containing solutions by adrenochrome sulfonate. The present study was undertaken to investigate if the same degradation pattern is found for the symphatomimetic compounds isoprenaline, dopamine, and metaraminol. It was found that isoprenaline and dopamine followed the same degradation pattern as epinephrine—they are photodegraded more rapidly in the presence of bisulfite than in its absence, probably by formation of an aminochrome sulfonate. Metraminol was photostable under the given conditions. The photostability of isoprenaline, dopamine, and epinephrine was further investigated in the infusion media sodium chloride (9 mg/ml), glucose (50 mg/ml), Macrodex® (dextran 70, 60 mg/ml, sodium chloride 9 mg/ml) and Ringer acetate. The influence of pH, conductivity, viscosity and media concentration were analyzed. In the presence of bisulfite it was found that Ringer acetate had a photodestabilizing effect, while Macrodex® had a slight photoprotective effect, on the catecholamines. The pH of the media was shown to be the most important factor, a low pH being protective. Glucose had a destabilizing effect on epinephrine, dopamine, and isoprenaline in the absence of bisulfite.