Pharmaceutical Research

, Volume 31, Issue 1, pp 194–203 | Cite as

Understanding Biorelevant Drug Release from a Novel Thermoplastic Capsule by Considering Microstructural Formulation Changes During Hydration

  • Zdravka Misic
  • Raphael Urbani
  • Thomas Pfohl
  • Katharina Muffler
  • Georg Sydow
  • Martin Kuentz
Research Paper



To study the biorelevant drug release from novel starch-based polyvinyl alcohol capsules (S-PVA-C). The effect of the shell material is studied by considering microstructural formulation changes during hydration.


Two different self-emulsifying systems containing either fenofibrate or probucol were filled in S-PVA-C, as well as capsules of gelatin (SGC) and starch (VegaGels®). Release analysis employed a BioDis® apparatus, while disintegration was studied by texture analysis. For microstructural analysis we used small angle x-ray scattering (SAXS).


S-PVA-C opened only partially in biorelevant media compared to completely opened SGC and VegaGels®. In case of the fenofibrate formulation, this opening mechanism caused only a short lag time, while the probucol formulation in S-PVA-C resulted in a sustained release. The latter formulation demonstrated much higher viscosity upon hydration compared to the fenofibrate system. Such a rheological effect on drug release was barely noted for SGC or VegaGels® and SAXS revealed differences in the hydrated microstructure.


Even though S-PVA-C are highly attractive for encapsulation of rather hydrophilic formulations, some care is needed regarding an immediate release form. The type of formulation hydration must be considered for adequate selection of the capsule material.


biorelevant release controlled hydration disintegration lipid-based formulation thermoplastic capsule 



Financial support of the Swiss Caps AG (member of the Aenova group) is gratefully acknowledged.


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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Zdravka Misic
    • 1
    • 2
  • Raphael Urbani
    • 3
  • Thomas Pfohl
    • 3
  • Katharina Muffler
    • 4
  • Georg Sydow
    • 4
  • Martin Kuentz
    • 1
  1. 1.Institute of Pharma TechnologyUniversity of Applied Sciences and Arts Northwestern Switzerland,MuttenzSwitzerland
  2. 2.Department of Pharmaceutical SciencesUniversity of BaselBaselSwitzerland
  3. 3.Department of ChemistryUniversity of Basel,BaselSwitzerland
  4. 4.Swiss Caps AG member of the Aenova group,KirchbergSwitzerland

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