Gelatin-based hydrogels for the controlled adsorption and release of model drugs

• Applicants: Dr. Alexander Southan; Professorin Dr. Cosima Stubenrauch
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 518557415

In order to obtain gelatin-based hydrogels, an aqueous solution of gelatin can be added to a mould and the gelatin can subsequently be gelled – either physically or chemically. This procedure is quite easy but leads to materials with very small surface areas, which is a disadvantage with regard to potential applications in drug release. In this project we will synthesise gelatin-based materials with large surfaces, namely hydrogel particles with radii between 50 and 100 µm and porous hydrogels with pore sizes between ~200 and 450 µm. Our ultimate goal is to control the diffusion paths of model drugs and thus their release kinetics via the size of the particles and the pores, respectively. The particle and pore sizes are chosen such that the maximum diffusion paths in the hydrogel matrix are comparable. Further control parameters for the release kinetics are the concentration of the drug and the isoelectric point (IEP) of the hydrogel. We will measure the release kinetics of the porous hydrogels as a function of the pore size, of the pore size distribution, of the porosity, and of the pore connectivity since these parameters control the diffusion paths in the hydrogel matrix. By analogy, we will measure the release kinetics of the particles as a function of the particle size as well as of the particle size distribution. We will specify the structure of the hydrogel particles and the porous hydrogels for which we obtain comparable release kinetics. In this way we will significantly increase our understanding of the structure-property-relationships of these materials. Materials with controllable release rates will be produced by finetuning the release kinetics with changes of both the IEP and the drug concentration. To produce these materials with the desired properties we will (1) synthesise and characterise gelatin-based hydrogel particles and porous hydrogels with tailor-made composition and structure and (2) investigate the adsorption and release behaviour of these materials for three different model drugs. Finally, we will study the release kinetics of selected samples in a physiological buffer at 37°C to simulate biologically relevant conditions.

• DFG Programme: Research Grants