The present invention provides a self-assembly of a compound or of a pharmaceutically acceptable salt thereof, the compound being represented by formula (I) €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ R 1 -Gly LeuAla Met Ala Pro Ser Val Gly His ValArg Gln His Gly-R 2 €ƒ€ƒ€ƒ€ƒ€ƒ (I) (wherein R 1 represents a linear or branched acyl group having 14 to 24 carbon atoms； R 2 represents OH, NH2, NR 3 R 4 , a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, or a substituted or unsubstituted aralkyloxy group； and R 3 and R 4 independently represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, an alkoxy group, or a hydroxy group, provided that both R 3 and R 4 do not represent a hydroxy group or an alkoxy group simultaneously).
