There are three PK studies of colistin levels in ELF and lung in humans.
For your reference:
1. Comparison of intrapulmonary and systemic pharmacokinetics of colistin methanesulfonate (CMS) and colistin after aerosol delivery and intravenous administration of CMS in critically ill patients.
Boisson M, Jacobs M, Grégoire N, Gobin P, Marchand S, Couet W, Mimoz O.