A partially cross-linked esterified cellulose ether having A) groups of the formula —C(O)—R—COOA or a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA, wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, and B) having a molecular weight distribution such that [Wf(>；100 k)−Wf(>；100 k)XL]/Wf(>；100 k)XL is at least 0.20, wherein Wf(>；100 k) is the total weight fraction of the esterified cellulose ether that exceeds 100,000 g/mol, and Wf(>；100 k)XL is the weight fraction that exceeds 100,000 g/mol of the methylated esterified cellulose ether is useful as enteric polymer for pharmaceutical dosage forms.
