Polyethylene glycol derivative, composition comprising same, and method for preparing bioactive polypeptide conjugate by using same

A polyethylene glycol derivative composition comprising:

• a polyethylene glycol derivative represented by Formula 1A;
• a polyethylene glycol derivative represented by Formula 2;
• and
• a polyethylene glycol derivative represented by Formula 3:
• wherein, in the composition,
• a content ratio of the polyethylene glycol derivative represented by Formula 1A within a range of number average molecular weight of 2950 to 3650 is at least 70 area % based on high performance liquid chromatography (HPLC),
• a content ratio of the polyethylene glycol derivative represented by Formula 2 within a range of number average molecular weight of 2950 to 3650 is 15 area % or less based on HPLC, and
• a content ratio of the polyethylene glycol derivative represented by Formula 3 within a range of number average molecular weight of 2950 to 3650 is 10 area % or less based on HPLC.

A method of preparing a physiologically active polypeptide conjugate, the method comprising:

• (a) a pegylation process in which a polyethylene glycol derivative of Formula 1 is reacted with a physiologically active polypeptide to generate a linkage in which the physiologically active polypeptide is covalently conjugated with an aldehyde carbon of the polyethylene glycol derivative of Formula 1;
• (b) a hydrolysis process in which the linkage is treated in an acidic aqueous condition to form a linkage hydrolyzate;
• and
• (c) a conjugation process in which the linkage hydrolyzate is reacted with an immunoglobulin Fc fragment or a derivative thereof to generate a conjugate, wherein
• the conjugate has a structure in which the Fc fragment or the derivative thereof is covalently conjugated with a carbon atom derived from an acetal carbon of the polyethylene glycol derivative of Formula 1 in the linkage hydrolyzate:
• wherein, in Formula 1, n is a natural number of 50 to 100, and
• R1 and R2 are C1-C5 alkyl that are identical to or different from each other.