An antibiotic composition for the treatment of bacterial infections, especially in the respiratory tract is provided. The antibiotic composition may include a mixture of gentamicin as active pharmaceutical ingredient (API), and a micronized poloxamer composition as excipient. Micronized poloxamer composition may be produced by mixing poloxamer 188 and poloxamer 407 in a suitable apparatus where a low-frequency acoustic field may be applied to facilitate mixing. Antibiotic composition may be obtained in powder form, or in solution, and may be administered by inhalation or irrigation. In other embodiments, a topical formulation of the antibiotic inhalation or irrigation composition may be produced. In some embodiments, other suitable poloxamers, or sugar alcohols may be employed as excipients. Due to the synergistic effect of micronized poloxamer composition, antibiotic composition may provide improved solubility and bioavailability of gentamicin, thus decreasing side effects and time of treatment.
