A novel pH-responsive superabsorbent hydrogel based on collagen for ephedrine controlled release

A novel family of ph-responsive polymeric hydrogel based on collagen was prepared for controlled delivery of ephedrine. acrylic monomers,acrylic acid (aa) and itaconic acid (ia) were simultaneously graft copolymerized onto collagen backbones by a free radical polymerization technique using ammonium persulphate (aps) as initiator and methylene bisacrylamide (mba) as a crosslinker. hydrogel formation was confirmed by ftir spectroscopy. thermogravimetric analysis showed the thermal stabilities of the hydrogels. results from scanning electron microscopy (sem) observation also showed a porous structure with smooth surface morphology of the hydrogel. swelling profiles obtained indicated clearly that these hydrogels swell slightly in a simulated gastric fluid (sgf) and strongly in a simulated intestinal fluid (sif). the model drug,ephedrine,was successfully loaded into the hydrogels and in vitro release studies were performed in sgf for the initial 122 min,followed by sif until complete dissolution. the release of ephedrine was continued up to 215 min. the release mechanism of the hydrogels was also studied using the ritger-peppas model.