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The importance of the molecular weight of ethyl cellulose on the properties of aqueous-based controlled release coatings

Kazlauske, Jurgita; Gårdebjer, Sofie LU ; Almer, Sara and Larsson, Anette (2017) In International Journal of Pharmaceutics 519(1-2). p.157-164
Abstract

Previous investigations of aqueous based ethyl cellulose (EC) latex dispersions have mainly focused on the commercially available viscosity grade 20 cps. In this study, dispersions of EC with varying viscosity grades (which correspond to molecular weights), ranging from 4 to 100 cps, were produced and characterised. The dispersions showed particle sizes around 200 nm and highly negative ζ-potentials (approx. −100 mV), which indicated stable dispersions as confirmed by sedimentation studies. The different latexes were used to produce free-standing film coatings. We hypothesised that the different viscosity grades of EC would result in different properties of the films. We found that an increase in viscosity grade (and higher molecular... (More)

Previous investigations of aqueous based ethyl cellulose (EC) latex dispersions have mainly focused on the commercially available viscosity grade 20 cps. In this study, dispersions of EC with varying viscosity grades (which correspond to molecular weights), ranging from 4 to 100 cps, were produced and characterised. The dispersions showed particle sizes around 200 nm and highly negative ζ-potentials (approx. −100 mV), which indicated stable dispersions as confirmed by sedimentation studies. The different latexes were used to produce free-standing film coatings. We hypothesised that the different viscosity grades of EC would result in different properties of the films. We found that an increase in viscosity grade (and higher molecular weight) resulted in lower coalescence between the particles during film formation and thus to higher water permeability than in film coatings of lower molecular weight. After exposure to water the EC 4 cps and 20 cps film coatings had a more porous structure in the side facing the air during production and drying after immersion in water. Molecular weight is therefore a factor that should be considered when producing pharmaceutical coatings for controlled release.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Coalescence, Ethylcellulose, Film coatings, Latex, Water permeability
in
International Journal of Pharmaceutics
volume
519
issue
1-2
pages
8 pages
publisher
Elsevier
external identifiers
  • scopus:85009863246
  • wos:000398005400016
ISSN
0378-5173
DOI
10.1016/j.ijpharm.2016.12.021
language
English
LU publication?
yes
id
1bcdab86-6dfa-4ec8-9fb4-cfbba70239e2
date added to LUP
2017-02-03 08:03:01
date last changed
2018-02-18 04:56:32
@article{1bcdab86-6dfa-4ec8-9fb4-cfbba70239e2,
  abstract     = {<p>Previous investigations of aqueous based ethyl cellulose (EC) latex dispersions have mainly focused on the commercially available viscosity grade 20 cps. In this study, dispersions of EC with varying viscosity grades (which correspond to molecular weights), ranging from 4 to 100 cps, were produced and characterised. The dispersions showed particle sizes around 200 nm and highly negative ζ-potentials (approx. −100 mV), which indicated stable dispersions as confirmed by sedimentation studies. The different latexes were used to produce free-standing film coatings. We hypothesised that the different viscosity grades of EC would result in different properties of the films. We found that an increase in viscosity grade (and higher molecular weight) resulted in lower coalescence between the particles during film formation and thus to higher water permeability than in film coatings of lower molecular weight. After exposure to water the EC 4 cps and 20 cps film coatings had a more porous structure in the side facing the air during production and drying after immersion in water. Molecular weight is therefore a factor that should be considered when producing pharmaceutical coatings for controlled release.</p>},
  author       = {Kazlauske, Jurgita and Gårdebjer, Sofie and Almer, Sara and Larsson, Anette},
  issn         = {0378-5173},
  keyword      = {Coalescence,Ethylcellulose,Film coatings,Latex,Water permeability},
  language     = {eng},
  month        = {03},
  number       = {1-2},
  pages        = {157--164},
  publisher    = {Elsevier},
  series       = {International Journal of Pharmaceutics},
  title        = {The importance of the molecular weight of ethyl cellulose on the properties of aqueous-based controlled release coatings},
  url          = {http://dx.doi.org/10.1016/j.ijpharm.2016.12.021},
  volume       = {519},
  year         = {2017},
}