Ziconotide Impurity 4

2- ((1R,4S,7S,13S,16R,21R,24S,27S,30S,33S,36S,39S,42R,45S,48S,54S,60S,63S,68R,71S,77S) -63-amino-13,45,54,60-tetrakis (4-aminobutyl) -16-carbamoyl-4,36-bis (3-guanidinopropyl) -27- (4-hydroxybenzyl) -71- ((R) -1-hydroxyethyl) -7,39,77-tris (hydroxymethyl) -33-isobutyl-48-methyl-30- (2- (methylthio) ethyl) -2,5,8,11,14,23,26,29,32,35,38,41,44,47,50,53,56,59,62,69,72,75,78,85-tetracosaoxo-18,19,65,66,81,82-hexathia-3,6,9,12,15,22,25,28,31,34,37,40,43,46,49,52,55,58,61,70,73,76,79,84-tetracosaazatricyclo[40.37.4.221,68]pentaoctacontan-24-yl) acetic acid