The release of water-soluble drugs from initially hydrated hydrogels matrices generally involves the simultaneous water absorption and drug desorption through a swelling-controlled diffusion mechanism. The diffusional behaviour of phenobarbitone from a hydrogel formed by a 2-hydroxyethylmethacrylate (HEMA) and methyl monoitaconate (MMI) copolymer was reported. The drug release into water was performed by high pressure liquid cromatography and the results showed that the phenobarbitone release from the hydrogels studies, considering the diffusion coefficient values did not change with the temperature and the polymerization method. The activation energy values suggested a more favorable phenobarbitone release from the hydrogels p(HEMA-co-MMI) polymerized in mass and bulk solution.
Controlled release; hydrogels; copolymers
