Lucinactant is a new synthetic peptide-containing surfactant for intratracheal use. It contains sinapultide, a novel, hydrophobic, 21-amino acid peptide (leucine and lysine repeating units, KL4 peptide) designed to mimic human surfactant protein-B (SB-P). More specifically, it mimics the C-terminal amphipathic helical domain of this protein. It also consists of phospholipids (dipalmitoylphosphatidylcholine, DPPC and palmitoyloleoyl phosphatidylglycerol, POPG) and a fatty acid (palmitic acid). It is completely devoid of animal-derived components.