The present invention provides compositions and methods for delivery to a lung tissue comprising a small interfering RNA (siRNA) capable of inhibiting expression of a gene, and a surfactant. In one aspect, a non-polymeric methods composition comprising a small interfering RNA (siRNA) capable of inhibiting expression of a gene, and a surfactant is disclosed. In other aspects, a method of inhibiting gene expression in a lung of a subject in need thereof and treating bronchopulmonary dysplasia in a lung of a subject also disclosed. The methods comprise administering a therapeutically effective amount of a non-polymeric composition to the lung of the subject, wherein the non-polymeric composition comprises a small interfering RNA (siRNA) capable of inhibiting expression of a gene, and a surfactant.