Supramolecular cyclodextrin pseudorotaxane hydrogels: A candidate for sustained release?

• Kinetics of protein release from PEO-α-CD pseudorotaxane hydrogels was studied.
• Erosion of the gel surface appeared to be the dominant factor for release of the proteins.
• The data was best described by zero order, power law and Hopfenberg model.

In this work, PEO-α-CD pseudorotaxane hydrogels were prepared. The gels were loaded with proteins, BSA and lysozyme, representing proteins with different molecular weights. The kinetics of protein release was studied. Factors such as PEO concentration, protein concentration and exposed surface area of the gels were investigated to understand their effects on the release of the encapsulated cargo. Erosion of the gel surface appeared to be the dominant factor for release of the proteins. Fitting the data to various models supported our hypothesis that the mechanism of release was primarily erosion-driven as the data was best described by zero order, power law and Hopfenberg model. The linear relationship between the amount of mass loss and time establishes the erosion of the polymer gel matrix to be the key factor for drug release.