Difelikefalin ,also known as D-Phe-D-Phe-D-Leu-D-Lys-[γ-(4-N-piperidinyl)amino carboxylic acid] (as the acetate salt), is an analgesic opioid peptide acting as a peripherally specific, highly selective agonist of the κ-opioid receptor (KOR).https://www.creative-peptides.com/product/difelikefalin-acetate-item-10-101-174-33660.html