Bioanalysis of six antibiotics from volumetricmicrosamples: a new tool for precisiondosing in critically ill children: supplementary materials

Background: Volumetric absorptive microsamples (VAMS) can support pharmacokinetic /pharmacodynamic studies. We present the bioanalytical method development for the simultaneousquantification of ampicillin, cefepime, ceftriaxone, meropenem, piperacillin, tazobactam , andvancomycin from VAMS. Methods & results: Optimal extraction, chromatographic , andmass spectrometryconditions were identified. Maximum extraction recoveries included 100 μl of water for rehydration andmethanol for protein precipitation. Chromatographic separation used Phenomenex Kinetex™ Polar C18column with a mobile phase comprising water/acetonitrile with formic acid and was fully validated.Hematocrit effects were only observed for vancomycin. Samples were stable for 90 days at -80◦C exceptfor meropenem, which was stable for 60 days. Conclusion: Multiple antibiotics can be assayed from asingle VAMS sample to facilitate pharmacokinetic/pharmacodynamic studies.