PEPTIDE DERIVATIVES

Biologically active novel peptide compounds are disclosed of the formula A-L-B-D-Lys-L-Phe-Gly-(L or D)Lys-L-Pro-L-Val-Gly-L-Lys-L-Lys-X or a pharmaceutically acceptable non-toxic functional derivative thereof; A is a N-terminal chain prolongation selected from the group consisting of (1) hydrogen and (2) N-acyl radicals derived from (a) alkyl carboxylic acids having from one to about six carbons, (b) aralkyl carboxylic acids having from seven to about ten carbons, (c) amino acids, (d) peptides, (e) the N-alkylcarbonyl or N-aralkylcarbonyl derivatives of the amino acids, and (f) the N-alkylcarbonyl or N-aralkylcarbonyl derivatives of the peptides; B is an amino-acid residue selected from the group consisting of Phe, Trp, Tyr, and -NH-CHR1-CO-, wherein R1 is hydrogen or alkyl from one to about six carbons; and X is a member selected from the group consisting of hydroxy, esterified hydroxy radicals, unsubstituted amino radicals and substituted amino radicals. Pharmaceutical compositions containing these compounds are also disclosed to take advantage of the valuable psychopharmacological properties thereof, such as utilization for the treatment for senility or, more generally, for a stimulation of the mental performance.