Modified hydroxypropyl methyl cellulose: Efficient matrix for controlled release of 5-amino salicylic acid.

Hydroxypropyl methyl cellulose has been modified by grafting synthetic polyacrylamide chains [g-HPMC (M)] in presence of microwave irradiation, which has used as carrier for controlled release of 5-amino salicylic acid (5-ASA). The FTIR and UV-vis-NIR studies reveal the excellent compatibility between g-HPMC (M) and 5-ASA. Field emission scanning electron microscopy (FESEM) and UV-vis-NIR analyses suggest that physical interaction predominates between the drug and matrix. % equilibrium swelling ratio (% ESR) of g-HPMC (M) decreased with addition of salt solutions and follow the order: Na(+)>K(+)>Mg(2+)>Ca(2+)>Al(3+). The in vitro 5-ASA release studies indicate that g-HPMC (M) delivers the drug preferentially in colonic region in more sustained way than that of HPMC. The 5-ASA release follows first order kinetics and non-Fickian diffusion mechanism. These favorable features make the graft copolymer a potential matrix for colon specific delivery of 5-ASA.