Stability study of epirubicin in NaCl 0.9% injection. 
To determine the stability of epirubicin in NaCl 0.9% injection under hospital storage conditions.  NaCl 0.9% solution was added to epirubicin lyophilized powder to make a final concentration of 1 mg/mL to study the degradation kinetics and 2 mg/mL to study the stability in polypropylene syringes under hospital conditions.  Physical chemistry laboratory, Unitat de Fisicoquímica, Universitat de Barcelona.  Solutions of epirubicin at 2 mg/mL in NaCl 0.9% solutions stored in plastic syringes were studied under hospital conditions at room temperature (25 +/- 1 degrees C) and under refrigeration (4 +/- 1 degrees C) both protected from light and exposed to room light (approximately 50 lumens/m2).  All samples were studied in triplicate and epirubicin concentrations were obtained periodically throughout each storage/time condition via a specific stability-indicating HPLC method.  To determine the degradation kinetics, solutions of epirubicin in NaCl 0.9% at 1 mg/mL were stored at different temperatures (40, 50, and 60 degrees C) to obtain the rate degradation constant and the shelf life at room temperature and under refrigeration.  The degradation of epirubicin in NaCl 0.9% solutions follows first-order kinetics.  The shelf life was defined as the time by which the epirubicin concentration had decreased by 10% from the initial concentration.  In this study, epirubicin was stable in NaCl 0.9% injection stored in polypropylene containers for all time periods and all conditions.  That results in a shelf life of at least 14 and 180 days at 25 and 4 degrees C, respectively.  The maximum decrease in epirubicin concentration observed at 25 degrees C and 14 days was 4%, and at 4 degrees C and 180 days was 8%.  The predicted shelf life obtained from the Arrhenius equation was 72.9 +/- 0.2 and 3070 +/- 15 days at 25 and 4 degrees C, respectively, in both dark and illuminated conditions.  Solutions of epirubicin in NaCl 0.9% at 2 mg/mL are chemically stable when they are stored in polypropylene syringes under hospital storage conditions.  No special precaution is necessary to protect epirubicin solutions (2 mg/mL) from light.