Developing an exogenous pulmonary surfactant-glucocorticoids association: Effect of corticoid concentration on the biophysical properties of the surfactant.

Glucocorticoids (GCs) are used to treat lung disease. GCs incorporated in an exogenous pulmonary surfactant (EPS) could be an alternative management to improve drug delivery avoiding side effects. In the development of these pharmaceutical products, it is important to know the maximum amount of GC that can be incorporated and if increasing quantities of GCs alter EPS biophysical properties. Formulations containing EPS and beclomethasone, budesonide or fluticasone were analyzed (PL 10mg/ml; GC 1-2mg/ml). The microstructure was evaluated by electron paramagnetic resonance spectroscopy, GCs incorporated were determined by UV absorption and polarized light microscopy and surfactant activity with pulsating bubble surfactometer. We found that GCs have a ceiling of incorporation of around 10wt%, and that the GC not incorporated remains as crystals in the aqueous phase without altering the biophysical properties of the surfactant. This fact is important, because the greater the proportion of GC that EPS can carry, the better the efficiency of this pulmonary GC system.