Process for producing cellulose derivatives of high bulk density and good flowability

Abstract

A particulate cellulose derivative is obtained in a process of grinding and drying a moist cellulose derivative which comprises the steps of A) providing a cellulose derivative having a moisture content of from 60 to 95 percent, based on the total weight of the moist cellulose derivative, B) grinding and partially drying the moist cellulose derivative in a gas-swept impact mill; and C) contacting the ground and partially dried cellulose derivative with an additional amount of a drying gas outside the gas-swept impact mill. The obtained particulate cellulose derivative has a high untapped bulk density and a good flowability.

1 .- 10 . (canceled) 
     
     
         11 . A particulate cellulose derivative having a median Equivalent Projected Circle Diameter (EQPC) of less than 140 micrometers, an untapped bulk density of at least 0.40 g/cm 3  and a Carr Index of 30 or less. 
     
     
         12 . The particulate cellulose derivative of  claim 11  having a Carr Index of 25 or less. 
     
     
         13 . The particulate cellulose derivative of  claim 11  having a median particle length of from 60 to 350 micrometers. 
     
     
         14 . The particulate cellulose derivative of  claim 11  having an onset dissolution temperature of at least 61.5° C. 
     
     
         15 . A dosage form produced from
 a) one or more cellulose derivatives of  claim 11 ,   b) one or more active ingredients, and   c) one or more optional adjuvants.   
     
     
         16 . (canceled) 
     
     
         17 . The particulate cellulose derivative of  claim 11  being one of methyl cellulose, methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose and hydroxypropyl cellulose. 
     
     
         18 . The particulate cellulose derivative of  claim 11  being hydroxypropyl methylcellulose. 
     
     
         19 . The particulate cellulose derivative of  claim 11  having an untapped bulk density of at least 480 g/l. 
     
     
         20 . The particulate cellulose derivative of  claim 18  having a Carr Index of 25 or less and a median particle length of from 60 to 350 micrometers.