“…Multiple groups have recently published research concerning SP and its analogues or derivatives as agonistic or antagonistic peptide NK1R ligands [7,8,19,21,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65]. New unnatural peptides are designed in order to improve their biological properties (e.g., half-life, receptor affinity and lipophilicity).…”