Several copolymer hydrogels were prepared from free radical copolymerization of 2-hydroxyethyl methacrylate (HEMA) with itaconic acid (IA). A series of Poly(2-hydroxyethyl methacrylate-co-itaconic acid) hydrogel, poly(HEMA-co-IA) were prepared at different feed monomer ratio using ammonium persulfate (APS) initiators in water at 70°C. The phytodrug 2,4-dichlorophenoxy acetic acid (2,4-D) were grafted to Poly(HEMA-co-IA) by esterification reaction. In addition, swelling behavior (Wt%) was studied at different pH. The hydrolysis of Poly(HEMA-co-IA)-2,4-D showed that the release of the bioactive compounds in aqueous phase, using Liquid-phase polymer-based retention (LPR) ultrafiltration system is dependent on the hydrophilic character as well as on pH value. The acid-hydrolysis of the herbicide from the conjugates follows a first order kinetics, showing higher kinetic constants as the pH increases. The base-catalyzed hydrolysis reaction of the herbicide follows a zero order kinetic, where the basic medium acts as a catalyst accelerating the release rate of the herbicide, showing higher kinetic constants as the pH increases. The differences in the release rates found for the hydrogel-herbicide at different pH can be correlated with the difference in their swelling capacity, where the release rate generally increases with an increase in the swelling capacity from water solution at higher pH. The study of the release process revealed that all samples in distilled water at pH 10 are representative of agricultural systems, showed first-order swelling kinetics and an absorption capacity that conforms to the parameters for hydrogels for agricultural application, which supports their potential for these purposes.