title: Microparticle surface layering through dry coating: impact of moisture content and process parameters on the properties of orally disintegrating tablets.
abstract: OBJECTIVE
  The aim of this study was to investigate the influence of process parameters during dry coating on particle and dosage form properties upon varying the surface adsorbed moisture of microcrystalline cellulose (MCC), a model filler/binder for orally disintegrating tablets (ODTs).
  
  
  METHODS
  The moisture content of MCC was optimised using the spray water method and analysed using thermogravimetric analysis. Microproperty/macroproperty assessment was investigated using atomic force microscopy, nano-indentation, scanning electron microscopy, tablet hardness and disintegration testing.
  
  
  RESULTS
  The results showed that MCC demonstrated its best flowability at a moisture content of 11.2% w/w when compared to control, comprising of 3.9% w/w moisture. The use of the composite powder coating process (without air) resulted in up to 80% increase in tablet hardness, when compared to the control. The study also demonstrated that surface adsorbed moisture can be displaced upon addition of excipients during dry processing circumventing the need for particle drying before tabletting.
  
  
  CONCLUSIONS
  It was concluded that MCC with a moisture content of 11% w/w provides a good balance between powder flowability and favourable ODT characteristics.
authors.affiliation: Aston School of Pharmacy, Aston University, Birmingham, UK.
authors.forename: Hamad
authors.initials: H
authors.lastname: Alyami
authors.affiliation: Aston School of Pharmacy, Aston University, Birmingham, UK.
authors.forename: Jasdip
authors.initials: J
authors.lastname: Koner
authors.affiliation: Aston School of Pharmacy, Aston University, Birmingham, UK.
authors.forename: Eman Z
authors.initials: EZ
authors.lastname: Dahmash
authors.affiliation: Department of Engineering and Innovation, Open University, Milton Keynes, UK.
authors.forename: James
authors.initials: J
authors.lastname: Bowen
authors.affiliation: Aston School of Pharmacy, Aston University, Birmingham, UK.|Children Hospital, Birmingham, UK.
authors.forename: David
authors.initials: D
authors.lastname: Terry
authors.affiliation: Aston School of Pharmacy, Aston University, Birmingham, UK.
authors.forename: Afzal R
authors.initials: AR
authors.lastname: Mohammed
mesh_terms: D000284:Administration, Oral; D002482:Cellulose / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D004339:Drug Compounding / Q000379:methods*; D005079:Excipients / Q000737:chemistry*; D006244:Hardness; D018625:Microscopy, Atomic Force / Q000379:methods; D008855:Microscopy, Electron, Scanning; D011208:Powders; D013607:Tablets; D013818:Thermogravimetry / Q000379:methods
chemical_list: D005079:Excipients; D011208:Powders; D013607:Tablets; D002482:Cellulose; C109691:microcrystalline cellulose
keywords: composite; disintegration; flowability; hardness; nano-indentation