Altering associations in aqueous solutions of a hydrophobically modified alginate in the presence of beta-cyclodextrin monomers

J Phys Chem B. 2006 Jan 12;110(1):190-5. doi: 10.1021/jp0518759.

Abstract

The formation of associative networks in semidilute aqueous solutions of hydrophobically modified alginate (HM-alginate) is dependent on intermolecular hydrophobic interactions. Addition of beta-cyclodextrin (beta-CD) monomers to the system provides decoupling of these associations via inclusion complex formation with the polymer hydrophobic tails. This results in a dramatic decrease in the viscoelastic response of the system and a more extended local structure of the polymer chains, as shown by small-angle neutron scattering (SANS) measurements. The zero-shear viscosity decreases about an order of magnitude when the beta-CD concentration is increased from 0 to 12 mm. The lifetime of the associative network decreases strongly with increasing levels of beta-CD addition. These findings clearly demonstrate that the hydrophobic association effect is efficiently reduced as the amount of beta-CD is increased. In the framework of drug delivery, this effect may be useful to improve the release of therapeutic molecules that can be entrapped in the polymer matrix.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alginates / chemistry*
  • Hydrophobic and Hydrophilic Interactions
  • Nephelometry and Turbidimetry
  • Neutron Diffraction / methods
  • Rheology
  • Solutions / chemistry
  • Water / chemistry
  • beta-Cyclodextrins / chemistry*

Substances

  • Alginates
  • Solutions
  • beta-Cyclodextrins
  • Water