Stability of dopamine hydrochloride exposed to blue-light phototherapy

The stability of dopamine hydrochloride in 5% dextrose injection when exposed to blue-light phototherapy was assessed. Solutions of dopamine hydrochloride (1000 micrograms/mL) were prepared, and samples were subjected to one of three light sources (fluorescent, dark, phototherapy) and two flow rates (2 mL/hr and no flow) at ambient room temperature. Irradiation levels were maintained between 5.1 and 6.6 microwatts/sq cm throughout the experiment. Samples obtained at 0 to 36 hours were assayed using high-performance liquid chromatography. There were no significant differences in dopamine stability among the sample groups exposed to the various light and flow conditions over the 36-hour study period. Dopamine hydrochloride in 5% dextrose injection exposed to phototherapy is stable for 36 hours at 1000 micrograms/mL. It is not necessary to protect dopamine solutions from blue-light irradiance to ensure clinically acceptable stability.