Micellized α-Cyclodextrin-Based Supramolecular Hydrogel Exhibiting pH-Responsive Sustained Release and Corresponding Oscillatory Shear Behavior Analysis

The fabrication of supramolecular hydrogels from micellized PLLA/DMAEMA/PEGMA polymers with alpha-CD has been explored to design injectable gel formulations for sustained drug release. The tricomponent hydrogels (5% w/ v)/alpha-CD (10% w/v) were able to sustain protein (BSA and lysozyme) release for 60-120 h at different pH conditions (pH 3, 7 and 10). In-depth rheological analysis highlighted the role of pH in tuning hydrogel behavior upon shear at microscopic level affecting protein release profiles. Protein release involved complex interactions within the network (isoelectric point and diffusion coefficient of the protein, pKa of DMAEMA, and pore size of the hydrogel). Lissajous Bowditch curves explained the microstructural response to increasing strain which weakened the supramolecular association and collapsed the formation of the porous hydrogel. Power Law was adopted to represent both transport mechanism and drug release phenomena. The release mechanism resulted from a combination of erosion- and diffusion-controlled release (non-Fickian and super case II).