Patent ID: 8536305

Claim:
A process for preparing a glatiramer polypeptide comprising L-tyrosine, L-alanine, L-glutamate and L-lysine, wherein said process comprises: (a) polymerizing a mixture of N-carboxyanhydride of L-tyrosine, N-carboxyanhydride of L-alanine, N-carboxyanhydride of a protected L-glutamate and N-carboxyanhydride of a protected L-lysine, in a polar aprotic solvent in the presence of an alkylamine initiator, to form a protected glatiramer polypeptide; (b) admixing an acid with the protected polypeptide formed in Step (a) and a solvent, to form a product; and (c) admixing a substance selected from the group consisting of diisopropylamine and isopropylamine with the product formed in Step (b), and water or a mixture of a solvent and water, to form a deprotected glatiramer polypeptide, wherein the acid used in Step (b) comprises an acid selected from the group consisting of acetic acid, hydrochloric acid, hydrogen bromide, hydrogen fluoride, methane sulfonic acid, trifluoromethane sulfonic acid, phosphoric acid, trifluoroacetic acid, sulfuric acid, and mixtures thereof.