Synthesis of Amphiphilic Hydrogels Based on Polyethylene glycole and Polycaprolactone for Drug Delivery Application

Hydrogels are presently under investigation as matrices for the controlled release of bioactive molecules, in particularpharmaceutical proteins, and for the encapsulation of living cells [1]. Hydrogels based on poly ethylene glycol (PEG) in combinationwith a biodegradable polyester have the advantages of biocompatibility and degradability and have thus found applications inbiomedical systems [2]. In this research, azide-functionalized polycaprolactone (PCL) and poly ethylene glycole were synthesized, separately. Afterwards, pentaerythritol was functionalized by alkyne groups by using of propargyl bromide. The functionalization of precursor was confirmed by IR and H-NMR spectroscopy. In the final step amphiphilic hydrogels were synthesized by coupling of azide and alkyne groups of precursors in the presence of Cu (I) and sodium ascorbate catalyst system (Click Chemistry). The amount of hydrophobic (PCL) and hydrophilic (PEG) parts of hydrogels were 25%-75%, 50%-50%, and 75%-25%, respectively. The results show, with increasing of PEG percentage in hydrogels structure, the swelling increased in water.