Synthesis of Biocompatible polyethylene glycol based hydrogel via Click Chemistry for the release of 2, 4-dichlorophenoxy acetic acid (2, 4-D) Herbicide

In the present study, biocompatible hydrogels based on polyethylene glycol with molecular weights 2000 and 4000 g/mol was synthesized by using click chemistry (Azide – Alkyne coupling). For this Perouse, the precursors were functionalized with azide and alkyne functional groups and then the hydrogels were synthesized by coupling reaction between azide and alkyne groups in the presence of copper sulfate and ascorbate sodium catalyst. Investigation of the morphology of these hydrogels well illustrated their network structure. The study of the swelling behavior of these hydrogels showed that the degree of swelling decreases with decreasing of polyethylene glycol molecular weight. These hydrogels were loaded with 2,4-dichlorophenoxy acetic acid herbicide. The obtained results showed that the rate and amount of herbicide release decrease with decreasing of polyethylene glycol molecular weight. In other words, the release amount of the herbicide decreases from 80% for the hydrogel with polyethylene glycol 4000 to 55% for the hydrogel with polyethylene glycol 2000. Hydrogels showed good stability in neutral buffer medium. It was also observed that drug release in both samples followed a non-Fickian mechanism.