Synthesis, Characterization, and Drug Release Behavior of Double Network Hydrogel of Alginate-Polyacrylamide Prepared by Inverse Miniemulsion Polymerization

A new method for the synthesis of double network hydrogel of polyacrylamide (PAM)-alginate (alg) with novel properties is described. A cooking oil, as an organic phase, and a solution consisting of sodium-alginate (Na-alg), acrylamide (AM), crosslinker, and initiator in water, as water phase, are used to produce Water in Oil (W/O) emulsion, stabilized by polyethylene glycol sorbitan monolaurate (Tween 80) at room temperature. CaCl2 nanoparticles are synthesized and dispersed in an oil medium and finally added to the emulsion. To obtain double network hydrogel, crosslinking agent N, Nʼ-methylenebisacrylamide (MBA), and Ca2+ cations are used for crosslinking of acrylamide and alginate polymers, respectively. Ca2+ nanoparticles in the oil phase move towards the aqueous droplets interface where dissolve into them and cause the formation of alginate networks. Furthermore, aqueous droplets, which contained a solution of AM, MBA, and ammonium persulfate (APS, as an initiator), act in the role of a reaction loci, and polymerization of AM are carried in these loci at 60 °C. These two polymer networks, synthesized in aqueous droplets, are interpenetrated to each other, and depending on the size of droplets, submicron double network hydrogel particles are formed. Prepared particles were employed for entrapping and releasing the model anticancer drug doxorubicin (DOX). The obtained double network hydrogels were characterized by Scanning Electron Microscopy (SEM), Fourier Transform InfraRed (FT-IR) spectroscopy, ThermoGravimetric Analysis (TGA), and Dynamic Light Scattering (DLS). In addition, swelling properties in water, adsorption, and release of model drugs were also studied.