Background and Objectives
Beta‐lactam antibiotics are reported for some of them to be subject to a rapid degradation in infusion solutions and in human blood samples. However, the current data of stability available in blood samples are limited to a few number of beta‐lactam antibiotics, and the methodology of the corresponding studies may be discussed. The objective of the present study is to evaluate the stability of 10 beta‐lactam antibiotics in human plasma samples.
Methods
Stability of amoxicillin, cefazolin, cefepime, cefotaxime, cefoxitin, ceftazidime, ceftriaxone, imipenem, meropenem, and piperacillin was evaluated at low and high concentrations at 20°C, 4°C, −20°C, and −80°C for 1, 7, 60, and 90 days, respectively.
Results
Amoxicillin, cefepime, meropenem, and piperacillin were the least stable antibiotics. The maximum durations allowing the stability for all the evaluated beta‐lactams at both tested concentrations were estimated at 3 h, 23 h, 10 days, and 35 days at 20°C, 4°C, −20°C, and −80°C, respectively.
Conclusion
We recommend to transport antibiotic plasma samples in ice at 4°C and even at −20°C if these samples come from external hospitals. Ideally, plasma samples should be stored at −80°C if possible; if not, the analysis of the samples should be performed as soon as possible in the limit of 10 days after a storage at −20°C.