Effective and efficient spreading of
drug formulations on the pulmonary mucosal layer is key to successful delivery of
therapeutics through the lungs. The pulmonary mucus layer, which covers the airway surface, acts as a barrier against therapeutic agents, especially in the case of chronic
lung diseases due to increased thickness and viscosity of the mucus. Therefore, spreading of the
drug formulations on the airways gets harder. Although spreading experiments have been conducted with different types of formulations on mucus-mimicking subphases, a highly effective formulation is yet to be discovered. Adding
surfactant to such formulations decreases the surface tension and triggers the Marangoni forces to enhance the spreading behavior. In this study, catanionic (cationic + anionic)
surfactant mixtures composed of
dodecyltrimethylammonium bromide (
DTAB) and
dioctyl sulfosuccinate sodium salt (AOT) mixed at various mole ratios are prepared and their spreading behavior on both
mucin and
cystic fibrosis (CF) mucus models is investigated for the first time in the literature. Synergistic interaction is obtained between the components of the
DTAB/AOT mixtures, and this interaction has enhanced the spreading of the formulation drop on both the
mucin and CF mucus models when compared with the spreading performances of selected conventional
surfactants. It is proposed that the catanionic
surfactant mixtures, especially when mixed at the molar ratios of 8/2 and 7/3 (
DTAB/AOT), improve the spreading even on the
cystic fibrosis sputum model. As it is vital to transport a sufficient amount of
drug to the targeted region for the treatment of diseases, this study presents an important application of the fundamentals of colloidal science to
pharmaceutical nanotechnology.