Esterified cellulose ethers of very low viscosity

摘要

An esterified cellulose ether which comprises (i) aliphatic monovalent acyl groups or (ii) 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, or (iii) a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA, and which has a) a viscosity of from 1.2 to 1.8 mPaos, measured as a 2.0 wt % solution of the esterified cellulose ether in 0.43 wt % aqueous NaOH at 20° C., or b) a viscosity of up to 5 mPa·s, measured as a 10 wt % solution of the esterified cellulose ether in acetone at 20° C., or c) a combination of the viscosities of a) and b), is useful for preparing solid dispersions comprising drugs.

主权项

1. An esterified cellulose ether
comprising (i) aliphatic monovalent acyl groups or (ii) 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, or (iii) a combination of aliphatic monovalent acyl groups and groups of the formula —C(O)—R—COOA, wherein the esterified cellulose ether has a) a viscosity of from 1.2 to 2.10 mPa·s, measured as a 2.0 wt. % solution of the esterified cellulose ether in 0.43 wt. % aqueous NaOH at 20° C., and b) a viscosity of up to 5 mPa·s, measured as a 10 wt. % solution of the esterified cellulose ether in acetone at 20° C. and wherein the esterified cellulose ether is produced by esterifying a cellulose ether having a viscosity of from 1.2 to 1.8 mPa·s, measured as a 2 wt. % solution in water at 20° C. with (i) an aliphatic monocarboxylic acid anhydride or (ii) a dicarboxylic acid anhydride or (iii) a combination of an aliphatic monocarboxylic acid anhydride and a dicarboxylic acid anhydride.