Stability of amoxicillin in portable pumps is drug concentration dependent.

Continuous amoxicillin infusion for deep infection's intravenous treatment is performed using elastomeric portable pumps carried under clothing and requires high doses of antibiotic. Therefore, we evaluated the stability of amoxicillin in those medical devices, with particular focus on both drug concentration and storage temperature. Stability of 20, 40, and 60g/L amoxicillin solutions in 300 mL portable pumps stored at 20 or 35 degrees C was studied by visual examination and drug concentration measurements at T0; T0 + 12 h; T0 + 24 h and; T0 + 48 h. Twenty and 40 g/L amoxicillin solutions were stable over 48 h, with a degradation rate that never exceeded 12% at T0 + 24 h, and 18% at T 0 + 48 h. However, the 60 g/L amoxicillin solution degradation rate was significant (p < 0.05, versus C1 and C2) at T0 + 24 h: 24.5 and 26.9% at 20 and 35 degrees C, respectively. This degradation process was amplified at T0 + 48 h, with degradation rates of 37 and 42% at 20 and 35 degrees C, respectively. Stability of amoxicillin in pump is guarantied over 48 h up to concentrations of 40 g/L. At 60 g/L major degradation of the antibiotic was observed.