| abstract |
A method for purifying an antibody, which is an anti-CD20 antibody, of a composition comprising the antibody and at least one contaminant, said method comprising the sequential steps of: (a) loading the composition into a cation exchange material in the that the composition is at a pH of 4.5 to 5.5 and has a conductivity of 2.5 to 5.5 mS / cm; (b) washing the cation exchange material with a first wash buffer, wherein the pH of the first wash buffer is 7.5 to 8.1, and where the first wash buffer comprises HEPES 15 to 35 mM and It has a conductivity of 0.5 to 1.5 mS / cm; (c) washing the cation exchange material with a second wash buffer, wherein the pH of the second wash buffer is 5.0 to 6.0, and where the second wash buffer comprises MES 14 to 23 mM and 5 to 15 mM NaCl and has a conductivity of 0.6 to 2.2 mS / cm; and (d) eluting the antibody from the cation exchange material with an elution buffer, in which the pH of the elution buffer is 5.3 to 5.7, and wherein the elution buffer comprises MONTH 14 to 23 mM and NaCl 140 to 180 mM and has a conductivity of 13.4 to 17.2 mS / cm. |