Synthetic lung surfactant having antioxidant properties

A method of treating respiratory distress syndrome in a subject in need thereof which comprises administering to the subject an effective amount of a mixture comprising a peptide and a lipid, or a peptide and a mixture of lipids wherein said peptide has the formula:

• X-Y-Z-Y'-Q 1
• or a pharmaceutically acceptable salt or optically active isomer thereof, wherein:
• X is hydrogen, a C.sub.1-5 alkyl group, a C.sub.1-10 acyl group, an amino acid, dipeptide or tripeptide;
• Y and Y' are each independently a bond,
• -(Set)n- where n is an integer of from 1 to 3, or T,
• wherein T is:
• ##STR17## n' is an integer from 1-8;
• W is --NHC(O)--, --NHCH.sub.2 --, --C(O)O-- --OC(O)--, --SC(O)--, or --SS--;
• and
• D is:
• ##STR18## wherein B is a bond, C.sub.1-16 alkylene, or C.sub.2-16 alkenylene, and B.sub.1 is B or ##STR19## wherein each R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.7 is independently a C.sub.1-6 alkyl;
• or X and Y together are Da-C(O)-- or Db-C(O)--;
• Q is hydroxy, amino, alkylamine, alkoxy group, --O-Da, or --O-Db;
• Z is a peptide residue of from 8 to 25 amino acid residues consisting of a fragment of the oligomer having the sequence
• -A.sub.1 -A.sub.2 -A.sub.3 -A.sub.4 -A.sub.5 -A.sub.6 -A.sub.7 -A.sub.8 -A.sub.9 -A.sub.10 -A.sub.11 -A.sub.1 '-A.sub.2 '-A.sub.3 '-A.sub.4 '-A.sub.5 '-A.sub.6 '- A.sub.7 '- A.sub.8 '-A.sub.9 '- A.sub.10 '-A.sub.11 '-A.sub.1 "-A.sub.2 "-A.sub.3 "-A.sub.4 "-A.sub.5 "-A.sub.6 "-A.sub.7 "-A.sub.8 "-A.sub.9 "-A.sub.10 "-A.sub.11 "-A.sub.1 '"-A.sub.2 '".
• and which begins with any one of the amino acid residues designated A.sub.1 -A.sub.11
• wherein
• A.sub.1, A.sub.1 ', A.sub.1 ", A.sub.1 '", A.sub.4, A.sub.4 ', A.sub.4 ", A.sub.8, A.sub.8 ', and A.sub.8 " are each independently selected from the group of hydrophilic amino acid residues consisting of -Glu-, -Asp-, -Ala-, -Gln-, -Asn-, -Gly-, -Ser-, -Thr-, -Lys-, -Arg-, -Orn-, and -hArg-;
• A.sub.2, A.sub.2 ', A.sub.2 ", A.sub.2 '", A.sub.3, A.sub.3 ', A.sub.3 ", A.sub.6, A.sub.6 ', A.sub.6 ", A.sub.7, A.sub.7 ', A.sub.7 ", A.sub.10, A.sub.10 ', and A.sub.10 " are each independently selected from the group of lipophilic amino acid residues consisting of -Leu-, -Nle-, -Met-, -Ala-, -Val- -Phe- -Nva- -Ile- and -Tyr-, or amino acid residue derivative T;
• A.sub.5, A.sub.5 ', A.sub.5 ", A.sub.11, A.sub.11 ', and A.sub.11 " are each independently selected from the group of basic amino acid residues consisting of -Lys-, -Orn-, -Arg-, or hArg-;
• A.sub.9, A.sub.9 ', A.sub.9 " are each independently selected from the group of lipophilic, neutral or basic amino acid residues consisting of -Leu-, -Nle-, -Met-, -Ala-, -Val-, -Phe-, -Nva-, -Ile-, -Tyr-, -Thr-, -Ser-, -Gln-, -Asn-, -Gly-, -Lys-, -Arg-, -hArg-, -Trp-, -Orn-, -Trp(For)-, or amino acid residue derivative T;
• with the proviso that there is at least one T, --O-Da, O-Db, Da-C(O) or Db-C(O)-- in formula 1;
• and
• said lipid or mixture of lipids is selected from the group consisting of DPPC, PC, CL, PG, PS, FA and TG.