Cation Mixed Mode (Anion exchangers)/Cation with hydrophobic interaction:

Positively charged hydrophobic ligands belong to the group of anion exchanger mixed mode (for example Capto MMC) (for example Capto MMC) (Melinda, US 20170058019)

Ligands comprising at least one acidic moeity such as a carboxyl group and also comprising at least one hydrophobic moeity such as a phenyl ring or an aliphatic hydrocarbon chain can be used (Gagnon, US 8,188,242).

A method of synthesising a multi-model cation exchanger media is disclosed in WO 03/24588.

(Johansson, J. Chromatogr A, 1016(1), 2003, pp. 35-49) discloses various ligands used in the synthesis of different multi-modal cation-exchangers.

Operating Conditions:

Washing/elution:

—ethylene glycol + Inorganic salt: 

Falkenstein (US13/883243, published as US Paent No: 9422329; see also US Patent Application No: 15/216099, published as US Patent 10377794 and US Patent Application 16/778,128, published as US 20200165297) discloses washing an antibody from a multimodal weak CEX such as Capto MMC or Streamline CST using ethylene glycol and an inorganic salt such as sodium chloride, potassium chloride and ammonium chloride. In some embodiments, a binding buffer comprising an inorganic salt and denaturant such as gaunidinium hydrochloride or urea is applied to the multimodal weak CEX.

Specific Types of Cation-Mixed Modal Resins:

Weak-Type Cation Mixed Mode:

–Capto-MMC: A mixed-mode chromatography support which exploits a combination of cation exchange and hydrophilic interaction functionalities is Capto-MMC. Capto-MMC is a weak cation-exchanger with a phenyl group for hydrophobic interactions and an amide group for hydrogen bonding.

Capto MMC is a multimodal cation exchanger and has a multimodal ligand that may interact with target molecules in several different ways. It contains a carboxylic group and thus its feautures partily resemble those of a weak cation exchanger. However, in addition, several other types of interactions are involved, including hydrogen bonding and hydrophobic interaction (GE Healthcare Data File 11-0035-45AA).

Liao (US 13/654574, published as US 2013/0102761) discloses a mixed mode chromatography that combines cationic exchange and hydrophobic functionalities with a large pore support matrix. Specifically, the mixed mode chromatography medium comprising a ligand which includes a hydrophobic group (aromatic and substituted (alkyl groups such as hexyl) aromatic groups such as a phenyl and biphenyl groups) joined to either a carboxyl or sulfogroup (—SO3H) by a peptide containing chain. A ligand contaning the linkage -C(O)-NH-CH2- between a carboxylic functionality as the weak cation exchange group and a phenyl functionality as the hydrophobic group is benzoylamino acetic acid. In embodiments in which the ligand is a benzamidoacetic acid or a 2-benzamidoethanesulfonic acid, a particularly convenient linkage between the phenyl ring of the ligand and the matrix is one in which the amine group of the linkage is bonded to the phenyl ring at a para-position relative to the carbonylamino acetic acid group in the case of the benzamidoacetic acid or to the carbonylaminoethylsufonic acid group in the case of the 2-benzmidoethanesulfonic acid. An example of a compound that can form both the ligand and at least part of the linkage is 4-aminobenzamidoacetic acid (also known as para-aminohippuric acid) and also 2-(4-aminobenzaido)ethanesulfonic acid. To couple a pendant amine-contianing ligand to a matrix with exposed vicinal diols, the diols can be oxidized to aldehyde groups and the aldehyde groups can then be couple to amine groups to form secondary amino linkages.

Synthetic Resins:

–-Methacrylate: Melter (J of Chromatography A, 1200 (2008) 156-165) disclose retention behavior of C-terminal MAb vartiants on Fractogel EMD COO- (s) which is a methacrylate based plymeric resin with carboxyl functional groups.

Cation, anion, and hydrophobic interaction:

Examples include ABxTM which is a mixed-mode ion exchanger designed for the purification of antibodies (see BAKERBOND ABx). 

Cation exchange and hydrophilic interaction:

Examples include Capto-STM which is a strong cation exchange and is a trademark of GE Healthcare Bio-Sciences.

Cation exchange + hydrophobic interaction + hydrogen bonding and pi-pi bonding:

Examples include Capto-MMCTM which is a multimodal cation exchange.