title: Novel film modifiers to alter the physical properties of composite ethylcellulose films.
abstract: OBJECTIVE
  Polyvinylpyrrolidone (PVP), molecular-composite PVP, and Plasdone S-630 copolyvidonum are potential polymeric film modifiers for achieving improved drug release. The aim of this study was to investigate how these polymeric additives would affect the physicomechanical properties of composite ethylcellulose films.
  
  
  METHODS
  The miscibility of these polymeric additives with ethylcellulose was determined from the differential scanning calorimetry (DSC) thermograms of various polymer blends formed from organic solvents. It was found that ethylcellulose (EC) was miscible with the polymeric additives up to a concentration of 50%. Ten percent to 30% w/w polymeric additives were then added to aqueous ethylcellulose dispersion to form composite films. The morphology, film transparency, dynamic mechanical analysis (DMA) thermograms, and mechanical properties of the composite ethylcellulose films were studied. In addition, puncture strength and % elongation of the dry and wet films were also compared from indentation test.
  
  
  RESULTS
  Significant reduction and change in film transparency and morphology was obtained for EC films blended with PVP of higher molecular weight (MW). The composite EC films also showed higher Tg, greater elastic modulus, tensile and puncture strength depending on the concentration and type of additives present.
  
  
  CONCLUSIONS
  The interaction between ethylcellulose and the polymeric additives is dependent on the MW and concentration of additives. The composite films offer new opportunities for the use of ethyl-cellulose as modified release coatings for dosage forms.
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore 117543, Singapore.
authors.forename: Lai Wah
authors.initials: LW
authors.lastname: Chan
authors.forename: Kang Teng
authors.initials: KT
authors.lastname: Ong
authors.forename: Paul Wan Sia
authors.initials: PW
authors.lastname: Heng
mesh_terms: D002482:Cellulose / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry*; D011108:Polymers / Q000032:analysis* / Q000737:chemistry*
chemical_list: D011108:Polymers; C013517:ethyl cellulose; D002482:Cellulose