Concentration vs time profile for piperacillin, at tissue steady state, in infected lung tissue, serum and healthy skeletal muscle after i.v. administration of 4 g piperacillin over 20 min. The minimum inhibitory concentration (MIC) against Pseudomonas aeruginosa is 64 mg l−1. •, Piperacillin in serum; ○, piperacillin in lung; ▪, tazobactam in serum; ◊, tazobactam in lung; … …, MIC against P. aeruginosa.