Development of colon specific microspheres of flurbiprofen for inflammatory bowel disease.

In the present investigation chitosan microspheres loaded with flurbiprofen (FLB) were prepared by oil/oil emulsification method for colon specific drug delivery. FLB was entrapped in chitosan microspheres, following coating with Eudragit S-100 utilizing the benefits of pH dependent solubility of Eudragit S-100, so as to prevent the premature release of FLB in upper GIT. Different batches of FLB microspheres were prepared by varying FLB: chitosan ratio (1:1 to 1:4). The effect of chitosan concentration on size, entrapment efficiency, percent drug loading and degree of swelling was evaluated. DSC studies revealed the dispersion of FLB in the matrix of chitosan microspheres. SEM analysis indicated the nearly smooth surface and spherical shape of the prepared microspheres. X-ray diffract gram of FLB microspheres showed less intense peaks as compared to free FLB. In vitro release studies of uncoated FLB- chitosan microspheres showed burst release in initial 4 h, while Eudragit S-100 coated microspheres prevented the premature release of FLB and showed controlled release for 12 h following Higuchi model, thus suitable for colon specific drug delivery.