Gelatin-Based Foamed and Non-foamed Hydrogels for Sorption and Controlled Release of Metoprolol

The influence of gelatin methacryloyl hydrogel morphology on the sorption and release behavior of metoprolol was studied for both equilibrium and non-equilibrium conditions. For samples examined in equilibrium conditions, no influence of the sample morphology was observed. The maximum sorption capacity qmax was determined to be 530 μmol g–1. Furthermore, up to 100% of the sorbed drug was released from both foamed and non-foamed samples upon immersion into salt solutions, which demonstrates the regenerability of the material. By contrast, the sample morphology strongly influenced the sorption and release kinetics. We found that the sorption and release rate coefficients k increased up to 10 times for foamed hydrogels as compared to non-foamed hydrogels. Furthermore, k increased with increasing ion concentration in the sorption and release medium. This effect was more pronounced for non-foamed hydrogels. The obtained results indicate that the sorption and release rate can be controlled by the morphology of the sorbents and, to some extent, by the ion concentration of the surrounding medium.