Colloid and Polymer Science

, Volume 292, Issue 1, pp 235–241 | Cite as

Rheological characterization of polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol graft copolymer (Soluplus®) water dispersions

  • Marco Cespi
  • Luca Casettari
  • Giovanni Filippo Palmieri
  • Diego Romano Perinelli
  • Giulia BonacucinaEmail author
Original Contribution


Soluplus® is a graft copolymer, with PEG and vinylcaprolactam/vinyl acetate side chains, recently available as excipient used to promote fast drug release in pharmaceutical dosage forms and as solubility enhancer. Despite this copolymer is reported to be able to act as a thickening additive and even as gelling agent as a function of temperature, there is a lack of information about the physical–chemical properties of its water dispersions. Thus, the aim of this paper is to investigate the influence of Soluplus® concentration and experimental temperature on the modification of the rheological properties of Soluplus® water dispersions. The results clearly indicated the influence of both the studied parameters and of their interactions on the Soluplus® thickening ability. Although some systems appear gel by human perception at 37 °C, the mechanical spectra demonstrated the lack of the formation of a tridimensional network structure. Overall, in all the analyzed temperatures and concentrations, the systems always behave as a “rheological” dilute or semidilute polymer solution.


Soluplus® Rheology Viscoelasticity Viscosity Gel 



The authors wish to thanks BASF (Lampertheim, Germany) for the generous donation of Soluplus®.

Supplementary material

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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Marco Cespi
    • 1
  • Luca Casettari
    • 2
  • Giovanni Filippo Palmieri
    • 1
  • Diego Romano Perinelli
    • 1
  • Giulia Bonacucina
    • 1
    Email author
  1. 1.University of Camerino, School of PharmacyCamerinoItaly
  2. 2.Department of Biomolecular SciencesUniversity of UrbinoUrbinoItaly

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