Esterified cellulose ethers of low acetone-insoluble content

US10526421B2 · kind B2 · utility

Inventors

• Oliver Petermann · Hamburg, DE
• Matthias Knarr · Nienburg/Weser, DE
• Matthias Sprehe · Walsrode, DE

Key dates

• Filing date: Aug 18, 2015
• Grant date: Jan 7, 2020
• Expiry date: Mar 11, 2036

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61K47/38
• WIPO field: Pharmaceuticals
• WIPO sector: Chemistry

Abstract

Esterified cellulose ethers which have i) as ester groups aliphatic monovalent acyl groups or 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 ii) a content of not more than 0.85 weight percent acetone-insoluble esterified cellulose ether particles, when the esterified cellulose ether is present in a mixture of 12.5 weight parts of esterified cellulose ether and 87.5 weight parts of acetone at 21° C., the weight percent acetone-insoluble esterified cellulose ether particles being based on the total weight of the esterified cellulose ether, wherein iii) not more than 14 percent of the acetone-insoluble esterified cellulose ether particles have a particle size of more than 90 micrometers.