Method for continuous production of degradation product of water-insoluble polymeric compound

A method for producing a degradation product of a water-insoluble polymeric compound, the method comprising, in the following order:

• (A) bringing a water-insoluble polymeric compound in a first aqueous medium into contact with a cation exchange resin to form a first mixture, heating the first mixture, and recovering a first supernatant comprising the degradation product;
• (B) adding a second aqueous medium to the cation exchange resin to form a second mixture, agitating and heating the second mixture, and recovering a second supernatant comprising the degradation product;
• (C) washing the cation exchange resin of (B) with a third aqueous medium and recovering a wash solution comprising the degradation product;
• (D) mixing the supernatant recovered in (A), the supernatant recovered in (B), and the wash solution recovered in (C) to obtain a fraction that has not adsorbed to the cation exchange resin and that comprises the degradation product;
• and
• (E) eluting the adsorbed fraction from the cation exchange resin and recovering an eluate, so as to obtain a fraction that has adsorbed to the cation exchange resin comprising residual degradation product,
• wherein the water-insoluble polymeric compound is a protein, a peptide or a saccharide, and wherein (A) and (B) are repeated 2 to 8 times when the water-insoluble polymeric compound is a protein or peptide or wherein (A) and (B) are repeated 2 to 5 times when the water-insoluble compound is a saccharide.