Eight-arm polyethylene glycol derivative, production method therefor, and modified bio-related substance thereof

A bio-related substance modified with an eight-arm polyethylene glycol moiety, wherein, the structure has at least one residue of a bio-related substance represented by D;

• when the number of the bio-related substance residue D in one molecule is greater than one, the D residues in one molecule are independently derived from the same bio-related substance, which can be the same or different residue groups;
• wherein, the eight-arm polyethylene glycol moiety has eight PEG chains and one octavalent central group CORE8 as represented by
• wherein, the moiety
• is denoted as “CORE” and consists of one tetravalent central group U and four trivalent branching groups E1, E2, E3 and E4;
• wherein, E1, E2, E3 and E4 are each independently identical or not identical in one molecule;
• wherein, L11, L12, L21, L22, L31, L32, L41 and L42 are divalent linking groups that respectively attaches a PEG chain to one of the eight ends of CORE;
• L11, L12, L21, L22, L31, L32, L41 and L42 can be each independently identical or not identical in one molecule;
• wherein, each D residue is independently attached to a PEG chain of the eight-arm polyethylene glycol moiety via a linking group L;
• wherein, L is a covalent linkage or a non-covalent linkage, wherein, the non-covalent linkage is a dihydrogen bond or a multiple hydrogen bond;
• when the number of D residues is greater than 1, the L groups have independent structures.