κ-Carrageenan Hydrogels as a Sustainable Alternative for Controlled Release of New Biodegradable Molecules with Antimicrobial Activities

The main objective of the present study was to develop κ-Carragenan (κ-CG) hydrogels by ionic crosslinking, using KCl and NaCl as crosslinkers, as medium controlled releasing of four new cleavable surfactants with antimicrobial activities (C10-MET; C14-MET; C10-BEN and C14-BEN) used as model drugs. The effect of the κ-CG amount on swelling behavior, morphological properties and load/release capacity of surfactants from hydrogels were investigated. The most efficient swelling result was observed for the sample containing a low ratio κ-CG/crosslinker when the swelling medium was distilled water. The hydrogels showed porous structure and elastic solid behavior in the analyzed temperature range (20–200 °C); and were able to load the four drugs by the classic entrapment method. The release results were closely related to the swelling values of the hydrogels and the solubility of the drug in the release medium. It was found that the drug release increased with time, reaching its maximum after 24 h, and C10-MET exhibited the highest percent release. The results of the present work indicate that the κ-CG hydrogels are good support materials for controlled release, with excellent swelling capacity (> 200%), which is a very important property for applications in agriculture.