Fig. 6.

Surface activity of synthetic lung surfactants measured with captive bubble surfactometry. Surface activity of synthetic lung surfactants was studied with a captive bubble surfactometer at 37°C. Synthetic surfactant preparations included Super Mini-B (S-MB) formulated with standard glycerophospholipids (DPPC:POPC:POPG 5:3:2 by weight) and Mini-B (MB) formulated with glycerophospholipids or the phospholipase-resistant lipid DEPN-8. Porcine SP-B in standard glycerophospholipids and Infasurf®, a bovine-derived clinical surfactant with both SP-B and SP-C, were studied as positive controls, while glycerophospholipids alone served as a negative control. Synthetic glycerophospholipid/peptide and DEPN-8 surfactants were all highly active in reducing minimum surface tension to ≤1 mN/m on the captive bubble surfactometer throughout 10 consecutive quasi-static compression-expansion cycles. Data are mean ± SEM for n = 4-8.