AAPS PharmSciTech

, Volume 19, Issue 1, pp 148–154 | Cite as

Cellulose Acetate Butyrate: Ammonio Methacrylate Copolymer Blends as a Novel Coating in Osmotic Tablets

  • R . Ali
  • M. Walther
  • R. BodmeierEmail author
Research Article


The objective of this work was the preparation of osmotic tablets using polymer blends of cellulose acetate butyrate (CAB) or ethylcellulose with ammonio methacrylate copolymer (Eudragit® RL). The advantage of these coatings in comparison to the traditionally used cellulose acetate is their solubility in safer organic solvents like ethanol. Polymer films were characterized with respect to their water uptake, dry mass loss, and mechanical properties. The effect of the polymer blend ratio on drug release and on the rupture force of the coating was investigated. In addition, the effect of drug solubility and content, pH and agitation rate of the release medium, and coating level and plasticizer content on the release were studied. With increased Eudragit® RL content in the coating blends, higher medium uptake of the film was observed, resulting in shorter lag times and faster drug release from the osmotic tablets. Replacing ethylcellulose with cellulose acetate butyrate as a coating material led to shorter lag times and faster drug release due to increased film permeability. In addition, CAB-based films had a higher strength and flexibility. The drug release was osmotically controlled and decreased with increasing coating level. It increased with increased drug solubility, plasticizer content, change of buffer species (acetate > phosphate), and decreased coating level. Agitation rate and drug content had no effect on the drug release. A 20% w/w coating level was sufficient for the tablet to tolerate forces of more than five times of the gastric destructive force reported in literature.


cellulose acetate butyrate ethylcellulose ammonio methacrylate copolymer osmotic tablets 


  1. 1.
    Liu L, Wang X. Solubility-modulated monolithic osmotic pump tablet for atenolol delivery. Eur J Pharm Biopharm. 2008;68:298–302.CrossRefPubMedGoogle Scholar
  2. 2.
    Santus G, Baker RW. Controlled release osmotic drug delivery: a review of the patent literature. J Control Release. 1995;35:1–21.CrossRefGoogle Scholar
  3. 3.
    Theeuwes F. Elementary osmotic pump. J Pharm Sci. 1975;64:1987–91.CrossRefPubMedGoogle Scholar
  4. 4.
    Shanbhag A, Barclay B, Koziara J, Shivanand P. Application of cellulose acetate butyrate-based membrane for osmotic drug delivery. Cellulose. 2007;14:65–71.CrossRefGoogle Scholar
  5. 5.
    Eastman. Cellulose acetate butyrate (CAB-553-0.4) product data sheet [Internet]. 2006. p. 1–2. Available from:
  6. 6.
    Eastman. Eastman cellulose esters for pharmaceutical drug delivery [Internet]. 2005. Available from:
  7. 7.
    Evonik. Eudragit RL PO, specification and test methods. Technical information. 2012.Google Scholar
  8. 8.
    Appel LE, Zentner GM. Use of modified ethylcellulose lattices for microporous coating of osmotic tablets. Pharm Res. 1991;8:600–4.CrossRefPubMedGoogle Scholar
  9. 9.
    Bodmeier R, Paeratakul O. Mechanical properties of dry and wet cellulosic and acrylic films prepared from aqueous colloid. Pharm Res. 1994;11:882–8.CrossRefPubMedGoogle Scholar
  10. 10.
    Okimoto K, Ohike A, Ibuki R, Aoki O, Ohnishi N. Factors affecting membrane-controlled drug release for an osmotic pump tablet ( OPT ) utilizing ( SBE ) 7 m - b -CD as both a solubilizer and osmotic agent. J Control Release. 1999;60:311–9.CrossRefPubMedGoogle Scholar
  11. 11.
    Moebus K, Siepmann J, Bodmeier R. Cubic phase-forming dry powders for controlled drug delivery on mucosal surfaces. J Control Release. 2012;157:206–15.CrossRefPubMedGoogle Scholar
  12. 12.
    Polli JE, Rekhi GS, Augsburger LL, Shah VP. Methods to compare dissolution profiles and a rationale for wide dissolution specifications for metoprolol tartrate tablets. J Pharm Sci. 1997;86:690–700.CrossRefPubMedGoogle Scholar
  13. 13.
    McClelland GA, Sutton SC, Engle K, Zentner GM. The solubility-modulated osmotic pump: in vitro/in vivo release of diltiazem hydrochloride. Pharm Res. 1991;8:88–92.CrossRefPubMedGoogle Scholar
  14. 14.
    Wyttenbach N, Alsenz J, Grassmann O. Miniaturized assay for solubility and residual solid screening (SORESOS) in early drug development. Pharm Res. 2007;24:888–98.CrossRefPubMedGoogle Scholar
  15. 15.
    Lentz KA, Tolle S, Sheskey PJ, Polli JE. Solubility and permeability determination of anhydrous theophylline with application to the biopharmaceutics classification system. Dow Chem. company, Midl. 2002.Google Scholar
  16. 16.
    Takka S, Rajbhandari S, Sakr A. Effect of anionic polymers on the release of propranolol hydrochloride from matrix tablets. Eur J Pharm Biopharm. 2001;52:75–82.CrossRefPubMedGoogle Scholar
  17. 17.
    Zentner GM, McClelland GA, Sutton SC. Controlled porosity solubility- and resin-modulated osmotic drug delivery systems for release of diltiazem hydrochloride. J Control Release. 1991;16:237–43.CrossRefGoogle Scholar
  18. 18.
    Bodmeier R, Guo X, Sarabia R, Shultety P. The influence of buffer species and strength on diltiazem HCl release from beads coated with aqueous cationic polymer dispersions, Eudragit RL RS. Pharm Res. 1996;13.Google Scholar
  19. 19.
    Bindschaedler C, Gurny R, Doelker E. Mechanically strong films produced from cellulose acetate latexes. J Pharm Pharmacol. 1987;39:335–8.CrossRefPubMedGoogle Scholar
  20. 20.
    Liu L, Khang G, Rhee J. Preparation and characterization of cellulose acetate membrane for monolithic tablet. Korea Polym J. 1999;7:289–96.Google Scholar
  21. 21.
    Liu L, Khang G, Rhee JM, Bang H. Monolithic osmotic tablet system for nifedipine delivery. J Control Release. 2000;67:309–22.CrossRefPubMedGoogle Scholar
  22. 22.
    Kamba M, Seta Y, Kusai A, Ikeda M, Nishimura K. A unique dosage form to evaluate the mechanical destructive force in the gastrointestinal tract. Int J Pharm. 2000;208:61–70.CrossRefPubMedGoogle Scholar

Copyright information

© American Association of Pharmaceutical Scientists 2017

Authors and Affiliations

  1. 1.College of PharmacyFreie Universität BerlinBerlinGermany
  2. 2.Pensatech Pharma GmbHBerlinGermany

Personalised recommendations