title: Enhanced film-forming properties for ethyl cellulose and starch acetate using n-alkenyl succinic anhydrides as novel plasticizers.
abstract: OBJECTIVE
  The aim of this study was to investigate the ability of n-alkenyl succinic anhydrides (n-ASAs) to improve the film-forming characteristics of a novel coating polymer, potato starch acetate degree of substitution 2.8 (SA). n-ASAs were also applied to improve the otherwise brittle properties of ethyl cellulose (EC) aqueous dispersion (Aquacoat) and EC solvent-based films.
  
  
  METHODS
  The effectiveness of two n-ASAs, 2-octenyl succinic anhydride (OSA) and 2-dodecen-1-ylsuccinic anhydride were evaluated as plasticizers. Mechanical properties, both water vapor and drug permeabilities, and glass transition temperatures of the cast free films were measured. Triethyl citrate and dibutyl sebacate were used as reference plasticizers.
  
  
  RESULTS
  The long hydrocarbon chain of n-ASA, with its accessible carbonyl groups, enabled a strong plasticization effect on the tested polymers. Due to the excellent mechanical properties (i.e., a tough film structure with considerable flexibility) and low permeability of the plasticized films, n-ASAs, and especially OSA proved to be an ideal plasticizer particularly for EC based coatings. Also, the EC aqueous dispersion plasticized with n-ASAs resulted in a markedly enhanced coalescence of the colloidal polymer particles, even at low drying temperatures.
  
  
  CONCLUSIONS
  In applications where a coating with high flexibility is required, n-ASAs can be used as plasticizers at moderately high concentrations (up to 60-70%, w/w) without losing the high tensile strength, excellent toughness and low permeability of EC and SA films.
authors.affiliation: Department of Pharmaceutics, University of Kuopio, P.O. Box 1627, FIN-70211, Kuopio, Finland. maarit.tarvainen@uku.fi
authors.forename: Maarit
authors.initials: M
authors.lastname: Tarvainen
authors.forename: Riitta
authors.initials: R
authors.lastname: Sutinen
authors.forename: Soili
authors.initials: S
authors.lastname: Peltonen
authors.forename: Hannu
authors.initials: H
authors.lastname: Mikkonen
authors.forename: Jaana
authors.initials: J
authors.lastname: Maunus
authors.forename: Kalle
authors.initials: K
authors.lastname: Vähä-Heikkilä
authors.forename: Vesa-Pekka
authors.initials: VP
authors.lastname: Lehto
authors.forename: Petteri
authors.initials: P
authors.lastname: Paronen
mesh_terms: D000465:Algorithms; D002152:Calorimetry, Differential Scanning; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002951:Citrates; D003460:Crystallization; D003998:Dicarboxylic Acids; D010539:Permeability; D010968:Plasticizers / Q000737:chemistry*; D012997:Solvents; D013213:Starch / Q000031:analogs & derivatives* / Q000737:chemistry*; D013387:Succinic Anhydrides / Q000737:chemistry*; D013718:Tensile Strength; D014867:Water
chemical_list: D002951:Citrates; D003998:Dicarboxylic Acids; D010968:Plasticizers; D012997:Solvents; D013387:Succinic Anhydrides; D014867:Water; C055481:dibutyl sebacate; C013517:ethyl cellulose; C023001:ethyl citrate; D002482:Cellulose; D013213:Starch; C050766:starch acetate