Synthesis and characterization of saponin-based supramolecular hydrogel structures

In this study, multifunctional hydrogel structures with drug release and high swelling properties were synthesized. Saponin groups were determined as the basic structural component in the hydrogel structures. In addition, biocompatible groups such as chitosan, starch, α-cellulose and β-cyclodextrin were used as monomer units. The structural flexibility of the hydrogels was provided by using poly(ethylene glycol) (PEG) units. In this way, multifunctional saponin-based hydrogels with properties that can be used as drug delivery systems were obtained. For the synthesis of these structures, firstly the PEG structure was converted to diglycidin ether structures with epichlorohydrin. Then, polymerizations were carried out in the presence of saponin and biocompatible monomer using the obtained diglycidin ether structures. As a result of the study, highly branched hydrogel structures with polyether structure were obtained. Hydrogel structures were basically synthesized in two groups. In the first group syntheses, the epoxy modified PEG structure was polymerized in the presence of polyol monomers at different ratios. In addition to, 12 different hydrogel structures were obtained in four groups using saponin, chitosan, starch, cellulose and β-cyclodextrin as polyol. In the second group of syntheses, 4′-chloro-2,2′:6′,2′′-terpyridine structure was added to the hydrogel system obtained from saponin and epoxy modified PEG structure and terpyridine functional hydrogel structures were obtained with metal-ligand interaction. The hydrogel structures prepared within the scope of the study were first characterized by Fourier transform infrared spectroscopy (FTIR) and elemental analysis. Their surface and morphological properties were examined by scanning electron microscope (SEM) and optical microscope. Thermal properties were determined by thermogravimetric analysis. Tetracycline was loaded into the obtained hydrogel structures and drug release properties were examined. As a result, it was observed that the hydrogel structures released a certain level of drug starting from the first 30 minutes and continued to release the drug regularly until the 30th hour.