SURFACTANT VERSUS SALINE AS A VEHICLE FOR CORTICOSTEROID DELIVERY TO THE LUNGS OF VENTILATED RABBITS

Local administration of steroids to the lungs in ventilated newborn in fants can minimize the harmful side effects that occur with systemic a dministration. An efficient system of drug delivery that provides unif orm distribution within the lungs is essential for the treatment of br onchopulmonary dysplasia. In this study we compare surfactant with 0.9 % saline solution as vehicles for the direct instillation of a steroid (budesonide) into the lungs. Twenty-two anesthetized, ventilated rabb its received [H-3]budesonide in either 0.9% saline or surfactant, admi nistered through an endotracheal tube. Before drug administration, bro nchial lavage was performed on half of the animals to serve as a model for surfactant deficiency. Lung samples were analyzed by both autorad iography (alveolar versus airway distribution) and liquid scintillatio n counting (central versus peripheral deposition). As expected, the de livered concentration of [H-3]budesonide decreased as airway size decr eased and branching increased. Significantly less [H-3]budesonide was deposited in the alveolar spaces of all study groups compared with tha t deposited in the small and large airways (p < 0.05). However, both v ehicles were equally efficient in delivering [H-3]budesonide to the lu ngs. Although the alveolar and peripheral areas received less (4-11%) of the drug than the central tissue (14-28%), this was consistent amon g all the groups and was not affected by altered lung compliance. Ther efore, either surfactant or saline could be used to efficiently and re liably deliver budesonide to the lungs at a level greater than that re ported using nebulizers. Because normal saline is currently used for t racheal toilette, it is likely to be preferred considering the increas ed costs associated with surfactant.