Physicochemical stability of furosemide in elastomeric devices at 1 and 10 mg/mL

Objectives Furosemide is a loop diuretic used for the rapid management of fluid overload and oedema associated with cardiac, renal or hepatic disorders. Intravenous furosemide can be administered either as a continuous infusion or as an intermittent bolus. This study aimed to evaluate the physicochemical stability of furosemide solutions at 1 and 10 mg/mL diluted in 0.9% NaCl in silicone elastomeric devices at 32°C to support continuous infusion in outpatient and home-based care settings. Stability was tested after preparation and after 6, 24 and 48 hours of storage. Methods Three portable elastomeric devices were prepared for each condition. Chemical stability was assessed by pH measurement and high-performance liquid chromatography (HPLC). The method was validated according to the International Conference on Harmonisation Q2(R2). At each time point of analysis the pH was measured and three samples from each device were analysed via HPLC. The solution is chemically stable if it retains more than 90% of its initial concentration, with the appearance of any degradation products monitored and if the pH variation is less than one unit. Physical stability was evaluated by visual and subvisual inspection using a particle counter. Results For both concentrations, visual and subvisual inspection was compliant at each analysis time. Physical stability was therefore demonstrated for both concentrations after 48 hours. Furosemide solutions at both concentrations maintained more than 90% of their initial concentration for 48 hours at 32°C. The pH decreased during the stability study. Conclusions The physicochemical stability of the furosemide solutions in elastomeric devices at 32°C was demonstrated for 24 hours at 1 mg/mL and for 48 hours at 10 mg/mL. The observed decrease in pH was the limiting factor in establishing the shelf life of the 1 mg/mL solutions. These findings support the use of continuous furosemide infusion in home care settings.