In this work, the mechanical properties and stability of alginate hydrogels containing functionalized alginates (peptide and β-cyclodextrin) were studied. There is an increasing interest in the modification of alginates to add functions such as cell attachment and increased solubility of hydrophobic drugs, for better performance in tissue engineering and drug release, respectively. Functionalization was achieved in this study via periodate oxidation followed by reductive amination, previously shown to give a high and controllable degree of substitution. Young’s modulus and the stress at rupture of the hydrogels were in general lowered when exchanging native alginate with the modified alginate. Still, the gel strength could be adjusted by the fraction of modified alginate in the mixed hydrogels as well as the degree of oxidation. No notable difference in deformation at rupture was observed while syneresis was influenced by the degree of oxidation and possibly by the nature and amount of the grafted molecules. The mixed hydrogels were less stable than hydrogels with only native alginate, and modified alginate was released from the hydrogels. Furthermore, the hydrogels in general rather disintegrated than swelled upon saline treatments.

Modification of drug delivery materials with beta‐cyclodextrins (β‐CyD) is known to increase solubility of poorly water‐soluble drugs, protect drugs from degradation and sustain release. In this study, we developed a hydrogel drug delivery system for local paclitaxel delivery using the natural polysaccharide alginate functionalized with β‐CyD‐moieties. Paclitaxel was chosen due to its ability to form inclusion complexes with cyclodextrins. The rheological and mechanical properties of the prepared hydrogels were characterized, as well as in vitro release of the paclitaxel and in vitro activity on PC‐3 prostate cancer cells. Introduction of β‐CyD‐moieties into the hydrogel reduces the mechanical properties of the gels compared to nonmodified gels. However, gelation kinetics were not markedly different. Furthermore, the β‐CyD‐modified alginate helped to reduce undesired crystallization of the paclitaxel in the gel and facilitated paclitaxel diffusion out of the gel network. Remarkably, the β‐CyD grafted alginate showed increased capacity to complex paclitaxel compared to free HPβ‐CyD. Release of both paclitaxel and degradation products were measured from the gels and were shown to have cytotoxic effects on the PC‐3 cells. The results indicate that functionalized alginate with β‐CyDs has potential as a material for drug delivery systems.