Provided are lipid antiinfective formulations substantially free of anionic lipids with a lipid to antiinfective ratio is about 1:1 to about 4:1, and a mean average diameter of less than about 1 .mu.m. Also provided is a method of preparing a lipid antiinfective formulation comprising an infusion process. Also provided are lipid antiinfective formulations wherein the lipid to drug ratio is about 1:1 or less, about 0.75:1 or less, or about 0.50:1 or less prepared by an in line fusion process. The present invention also relates to a method of treating a patient with a pulmonary infection comprising administering to the patient a therapeutically effective amount of a lipid antiinfective formulation of the present invention. The present invention also relates to a method of treating a patient for cystic fibrosis comprising administering to the patient a therapeutically effective amount of a lipid antiinfective formulation of the present invention.