title: Coprocessing of cellulose II with amorphous silicon dioxide: effect of silicification on the powder and tableting properties.
abstract: OBJECTIVE
  In recent years, coprocessing has been the most successful approach to improve and correct the functionality of excipients. The aim of this study is to coprocessed cellulose II with SiO(2) and to evaluate the resulting powder and tableting properties.
  
  
  METHODS
  Novel cellulose II:SiO(2) (98:2, 95:5, 90:10 and 80:20 w/w ratios) composites were produced by spray drying, wet granulation and spheronization techniques and the resulting powder and tableting properties were assessed.
  
  
  RESULTS
  Cellulose II:SiO(2) composites produced by spray- drying exhibited spherical/oblongate shape, narrow distribution and mean diameter from 51 to 75 µm. The composites produced by wet granulation had larger distribution, granular shape and a mean diameter from 105 to 129 µm. The spheronized composites showed the highest size (from 148 to 450 µm) and round shape. Bulk and tap densities and flow were reduced as the silicification level increased in the spray dried and wet granulated materials. Likewise, silicification increased the true density, porosity and surface roughness of these materials. Water sorption decreased only at silicification level of 20% being comparable to the ones shown by Prosolv(®) samples. Contact angles of all cellulose II materials were lower than those of cellulose I except for Celphere203 indicating better wettability. A 5% and 10% silicification levels rendered the strongest compacts for the spray dried and wet granulated materials, respectively. Silicification did not affect the fast disintegration properties of MCCII.
  
  
  CONCLUSIONS
  Coprocessing proved to be useful tool to modify the powder and tableting properties of cellulose II.
authors.affiliation: Division of Pharmaceutics and Translational Therapeutics, College of Pharmacy, The University of Iowa, Iowa City, Iowa 52242, USA. jhon-rojascamargo@uiowa.edu
authors.forename: John
authors.initials: J
authors.lastname: Rojas
authors.forename: Vijay
authors.initials: V
authors.lastname: Kumar
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods*; D005079:Excipients / Q000737:chemistry*; D010316:Particle Size; D011208:Powders / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D013607:Tablets / Q000737:chemistry
chemical_list: D005079:Excipients; D011208:Powders; D013607:Tablets; D012822:Silicon Dioxide; D002482:Cellulose