EFFECT OF LIPIDS AND OTHER SUBSTANCES ON THE ADSORPTION OF DIPALMITOYL PHOSPHATIDYLCHOLINE

The effect of various lipids, proteins and other substances [limb- and human-derived] on the adsorption rate of dipalmitoyl phosphatidylcholine (DPC) was investigated. Each substance was added to a sonicated suspension of DPC in saline and the surface pressure of the adsorbed surface film was measured using a platinum plate suspended from an electrobalance. Pure DPC adsorbed very slowly being complete only after 8 h; its half-adsorption time was 91.8 .+-. 8.3 min. Four additives markedly reduced the half-adsorption time of DPC: dipalmitoyl phosphatidylglycerol (1.1 .+-. 0.2 min), phosphatidylinositol (2.8 .+-. 0.4 min), serum high-density lipoprotein (1.0 .+-. 0.2 min) and surfactant apoprotein (0.9 .+-. 0.1 min). The half-adsorption times of mixtures of DPC and the other additives ranged 15.3 .+-. 1.9 to 107.8 .+-. 12.1 min. Dipalmitoyl phosphatidylglycerol, phosphatidylinositol and serum high-density lipoprotein, in combination with dipalmitoyl phosphatidylcholine, may be of value in the treatment of respiratory distress syndrome in the human neonate.