Inhibitory effects of fibrinogen on the dynamic tension-lowering activity of dipalmitoyl phosphatidylcholine dispersions in the presence of tyloxapol

Abstract.

Inhibitory effects of fibrinogen on the dynamic surface tension-lowering ability of dipalmitoyl phosphatidylcholine (DPPC)/tyloxapol dispersions at pulsating air/liquid interfaces were investigated. When 10 ppm tyloxapol was added into a 1000 ppm DPPC dispersion prepared by sonication alone, the dynamic surface activity of the mixture was controlled by DPPC and was significantly inhibited by the presence of 1000 ppm fibrinogen. If the added tyloxapol concentration was as high as 100 ppm, tyloxapol then dominated the dynamic adsorption behavior of the dispersion, and the addition of 1000 ppm fibrinogen only showed minor influence on the dynamic surface tension behavior. When a 1000 ppm DPPC dispersion was prepared by sonication with 10 ppm tyloxapol, improved dynamic adsorption behavior resulted and thus the fibrinogen inhibition on the dynamic surface tension-lowering activity of the dispersion was slightly lessened. If the concentration of tyloxapol present during the sonication of a 1000 ppm DPPC dispersion was increased to 100 ppm, less interference by tyloxapol and/or fibrinogen with the dynamic adsorption of DPPC was found, which appears related to the tyloxapol-enhanced DPPC dispersion status with a reduced particle size.