abstract |
(57) [Summary] (Modified) [Problem] To provide an excellent analgesic substance [Solution] (Wherein n is the same or different and represents 1-8) or an opioid peptide derivative or a salt thereof. Especially 5- Methyl-3,6-bis [4- (2 ', 6'-dimethyltyrosyl) aminobutyl] -2- (1H) -pyrazinone and salts thereof. |