In vitro controlled release of colon targeted mesalamine from compritol ATO 888 based matrix tablets using factorial design

A controlled release matrix formulation for mesalamine was designed and developed to achieve a 24 h release profile. Using compritol 888 ATO (glyceryl behenate) as an inert matrix-forming agent to control the release of mesalamine, formulation granules containing the solid dispersions were investigated. Pectin, a polysaccharide, was used as bacterial dependent polymer for colon targeting. The matrix tablets for these formulations were prepared by direct compression and their in vitro release tests were carried out. A 3(2) full factorial design was used for optimization by taking the amounts of glyceryl behenate (X(1)) and pectin (X(2)) as independent variables and percentage drug released at 2 (Q(2)), 16 (Q(16)) and 24 (Q(24)) h as dependent variables. Drug release from the matrix tablets formulations lasted for over 24 h. Images of the tablet surface and cross-section were characterized by scanning electron microscopy to show the formed pores and channels in the matrices. These may provide the release pathway for the inner embedded drugs. The co-mixing of polysaccharide pectin, into the waxy matrices played a meaningful role in targeting the tablets to colon. The drug release from the novel formulation may be attributed to the diffusion-controlled mechanism. The results of the full factorial design indicated that an optimum amount of compritol ATO 888 and a high amount of pectin favors the colon targeting and controlled release of mesalamine from dosage form.