RESUMO
BACKGROUND: Most previous stability studies for norepinephrine have reported the percentage of drug remaining in IV solutions after only 24 h. No previously published study has evaluated the effect of light on the stability of this drug. OBJECTIVE: To evaluate the stability of norepinephrine (64 mg/L) in either normal saline (NS; 0.9% sodium chloride) or 5% dextrose in water (D5W) with storage at either 4°C or room temperature (23°C) in polyvinyl chloride (PVC) bags exposed to or protected from normal room lighting for 2 months. METHODS: Thirty-two PVC bags were prepared, each containing norepinephrine at 64 mg/L; half of the bags had normal saline as the diluent and the other half had D5W. The bags were stored at either 4°C or room temperature (23°C), with protection from or exposure to ambient fluorescent room light. Overall, there were 4 bags for each combination of diluent, temperature, and light condition. The concentration of norepinephrine in each bag was determined by a validated, stability-indicating liquid chromatographic method on study days 0, 1, 2, 3, 4, 8, 9, 10, 11, 14, 18, 21, 23, 25, 28, 30, 36, 42, and 61. RESULTS: Analysis of variance revealed differences in percentage remaining as a function of study day (p < 0.001) and light conditions (p < 0.001), but not diluent (p = 0.06) or storage temperature (p > 0.99). CONCLUSIONS: Solutions of norepinephrine 64 mg/L in NS or D5W can be stored in PVC bags at 4°C for up to 61 days with protection from light. This expiry date allows for up to 24 h storage at 23°C. Solutions that are not protected from light will retain only 90% of the initial concentration after storage for 39 days at 4°C. This storage period could include up to 24 h at room temperature, without protection from light.