title: The Development of Direct Extrusion-Injection Moulded Zein Matrices as Novel Oral Controlled Drug Delivery Systems.
abstract: OBJECTIVE
  To evaluate the potential of zein as a sole excipient for controlled release formulations prepared by hot melt extrusion.
  
  
  METHODS
  Physical mixtures of zein, water and crystalline paracetamol were hot melt extruded (HME) at 80°C and injection moulded (IM) into caplet forms. HME-IM Caplets were characterised using differential scanning calorimetry, ATR-FTIR spectroscopy, scanning electron microscopy and powder X-ray diffraction. Hydration and drug release kinetics of the caplets were investigated and fitted to a diffusion model.
  
  
  RESULTS
  For the formulations with lower drug loadings, the drug was found to be in the non-crystalline state, while for the ones with higher drug loadings paracetamol is mostly crystalline. Release was found to be largely independent of drug loading but strongly dependent upon device dimensions, and predominately governed by a Fickian diffusion mechanism, while the hydration kinetics shows the features of Case II diffusion.
  
  
  CONCLUSIONS
  In this study a prototype controlled release caplet formulation using zein as the sole excipient was successfully prepared using direct HME-IM processing. The results demonstrated the unique advantage of the hot melt extruded zein formulations on the tuneability of drug release rate by alternating the device dimensions.
authors.affiliation: Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Wageningen, The Netherlands, jacob.bouman@wur.nl.
authors.forename: Jacob
authors.initials: J
authors.lastname: Bouman
authors.forename: Peter
authors.initials: P
authors.lastname: Belton
authors.forename: Paul
authors.initials: P
authors.lastname: Venema
authors.forename: Erik
authors.initials: E
authors.lastname: van der Linden
authors.forename: Renko
authors.initials: R
authors.lastname: de Vries
authors.forename: Sheng
authors.initials: S
authors.lastname: Qi
mesh_terms: D002152:Calorimetry, Differential Scanning; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004058:Diffusion; D004337:Drug Carriers / Q000737:chemistry; D004339:Drug Compounding; D016503:Drug Delivery Systems; D005079:Excipients / Q000737:chemistry*; D005583:Fourier Analysis; D012995:Solubility; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared; D013607:Tablets; D014961:X-Ray Diffraction; D015028:Zein / Q000737:chemistry*
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005079:Excipients; D013607:Tablets; D015028:Zein