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Poly(acrylic acid)-grafted hydrophobic weak acid gels as mucoadhesives for controlled drug release

Abstract:

Hydrophobic weak acid gel discs of poly(methacrylic acid-co-methyl methacrylate) were grafted with poly(acrylic acid) by the gamma pre-irradiation method. Experimental grafting variables including radiation dose, monomer concentration, reaction time and temperature, were evaluated. Grafting was demonstrated by SEM, FTIR-ATR, TGA and DSC. The contact angle between water and the gel's surface increased with low grafting levels due to the rough surfaces created by the grafting of poly(acrylic acid) chains. Ex-vivo mucoadhesive tests using pig's intestinal mucosa showed a significant increase in the detachment and adhesion strengths of the grafted gels compared to the non-grafted ones. Our results demonstrate the effect of the flexible chains found on the surface of the gels in the mucoadhesive properties of the materials analyzed. Sustained drug delivery of the model drug –salicylamide– was achieved at pH values commonly found in the intestinal tract. These grafted gels show great potential as mucoadhesive, controlled-release systems.