Behavior of thin liquid films from aqueous solutions of a pulmonary surfactant in presence of corticosteroids

Abstract

Therapeutic pulmonary surfactants are currently investigated in clinical medicine as corticosteroids delivery vehicles into the lung. The influence of the corticosteroids Budesonide and Beclometasone dipropionate on the surface properties of aqueous solutions of the therapeutic surfactant preparation Curosurf® has been studied using the black foam film and the wetting film methods. The measurements of probability W for black foam film formation versus surfactant concentration C indicated that the two characteristics of black foam film stability – critical concentration Cc and threshold concentration Ct – for Curosurf® mixtures with 3μg/cm3 corticosteroids practically coincide with the values for Curosurf® alone. The disjoining pressure/black film thickness isotherms for mixtures of Curosurf®+corticosteroids are slightly shifted to larger film thicknesses compared to isotherm of Curosurf® alone. The measurements of wetting film thickness and wetting contact angles showed that the hydrophobization of SiO2-solid surface by mixtures of Curosurf®+corticosteroids is slightly smaller than the hydrophobization due to Curosurf® only. Budesonide and Beclometasone dipropionate equally influence the wetting behaviour of the Curosurf® solutions. These results indicate that the addition of corticosteroids does not alter significantly the surface properties of the therapeutic pulmonary surfactant.