This study will evaluate systemic and urine pharmacokinetics in spontaneously breathing healthy volunteers following a single dose of amikacin/fosfomycin, using the PARI Investigational eFlow Nebulizer System or the PARI LC Sprint Nebulizer. Three doses (30/12 mg, 60/24 mg, 90/36 mg amikacin/fosfomycin) will be evaluated. Following this evaluation, a single dose and nebulizer will be chosen to further evaluate systemic, bronchoalveolar, and urine pharmacokinetics in spontaneously breathing healthy volunteers.