Pulmonary and systemic pharmacokinetics of colistin methanesulfonate (CMS) and formed colistin following nebulisation of CMS among patients with ventilator-associated pneumonia

•CMS and formed colistin were notably higher (∼100- to 600-fold) in ELF than plasma after nebulisation of 3 and 5 MIU CMS.•Free ELF concentrations of formed colistin were approximately 1- to 10-fold higher than the median MIC.•Concomitant intravenous administration of CMS has minimal impact on formed colistin concentrations in ELF.•Plasma formed colistin concentrations after nebulisation were constantly lower than those associated with nephrotoxicity.