Chapter 3 - Interfacial properties of therapeutic pulmonary surfactants studied by thin liquid films

Abstract

The pulmonary surfactants are considered predominantly from the perspective of surfactant insufficiency in preterm newborns developing respiratory distress syndrome (RDS). Currently, lung extracts of animal origin, known as therapeutic pulmonary surfactants, are largely used in RDS treatment. We introduced a new in vitro method for the study of therapeutic pulmonary surfactants based on the model black foam film, including bilayer film. Microscopic foam films from aqueous surfactant solutions are explored by means of interferometric technique which provides for introducing new parameters and measuring new dependences characterising interfacial properties of therapeutic pulmonary surfactants. Film thickness, probability of black film formation and disjoining pressure are measured. The wetting properties of surfactant solutions are studied. Interfacial characteristics such as minimal surfactant concentration to obtain black film and concentration at which a black film is 100% obtained are determined. The following therapeutic pulmonary surfactants are studied: Curosurf, Infasurf, Survanta, Alveofac and Exosurf.