TY  - JOUR
A1  - Bertz, Andreas
A1  - Wöhl-Bruhn, Stefanie
A1  - Miethe, Sebastian
A1  - Tiersch, Brigitte
A1  - Koetz, Joachim
A1  - Hust, Michael
A1  - Bunjes, Heike
A1  - Menzel, Henning
T1  - Encapsulation of proteins in hydrogel carrier systems for controlled drug delivery influence of network structure and drug size on release rate
JF  - Journal of biotechnology
N2  - Novel hydrogels based on hydroxyethyl starch modified with polyethylene glycol methacrylate (HES-P(EG)(6)MA) were developed as delivery system for the controlled release of proteins. Since the drug release behavior is supposed to be related to the pore structure of the hydrogel network the pore sizes were determined by cryo-SEM, which is a mild technique for imaging on a nanometer scale. The results showed a decreasing pore size and an increase in pore homogeneity with increasing polymer concentration. Furthermore, the mesh sizes of the hydrogels were calculated based on swelling data. Pore and mesh size were significantly different which indicates that both structures are present in the hydrogel. The resulting structural model was correlated with release data for bulk hydrogel cylinders loaded with FITC-dextran and hydrogel microspheres loaded with FITC-IgG and FITC-dextran of different molecular size. The initial release depended much on the relation between hydrodynamic diameter and pore size while the long term release of the incorporated substances was predominantly controlled by degradation of the network of the much smaller meshes.
KW  - Hydrogel
KW  - Hydrogel microspheres
KW  - Network structure
KW  - Release studies
KW  - Protein delivery
KW  - Mesh size
Y1  - 2013
U6  - https://doi.org/10.1016/j.jbiotec.2012.06.036
SN  - 0168-1656
VL  - 163
IS  - 2
SP  - 243
EP  - 249
PB  - Elsevier
CY  - Amsterdam
ER  -