Formulation development and optimization of bilayer tablets of aceclofenac

Objective: The objective of the present study was to develop bilayer tablets of aceclofenac that are characterized by initial burst drug release followed by sustained release of drug. Methods: The fast-release layer of the bilayer tablet was formulated using microcrystaline cellulose (MCC) and HPMC K4M. The amount of HPMC E4M (X-1) and MCC (X-2) was used as independent variables for optimization of sustained release formulation applying 3(2) factorial design. Three dependent variables were considered: percentage of aceclofenac release at 1 h, percentage of aceclofenac release at 12 h, and time to release 50% of drug (t(50%)). The composition of optimum formulation of sustained release tablets were employed to formulate double layer tablets. Results: The results indicate that X-1 and X-2 significantly affected the release properties of aceclofenac from sustained release formulation. The double layer tablets containing fast-release layer showed an initial burst drug release of more than 30% of its drug content during first 1 h followed by sustained release of the drug for a period of 24 h. Conclusion: The double layer tablets for aceclofenac can be successfully employed as once-a-day oral-controlled release drug delivery system characterized by initial burst release of aceclofenac for providing the loading dose of drug.