Development of three layered buccal compact containing metoprolol tartrate by statistical optimization technique

The objective of this work to evaluate the effect of formulation variables on release properties and bioadhesive strength in development of three layered buccal compact containing highly water-soluble drug metoprolol tartrate (MT) by statistical optimization technique. Formulations were prepared based on rotatable central composite design with peripheral polymer ratio (carbopol 934P: HPMC 4KM) and core polymer ratio (HPMC 4KM: sodium alginate) as two independent formulation variables. The three layered buccal compact comprises a peripheral layer, core layer and backing layer. Four dependent (response) variables were considered: bioadhesion force, percentage MT release at 8 h, T50% (time taken to release 50% of drug) and release exponent (n). The release profile data was subjected to curve fitting analysis for describing the release mechanism of MT from three layered buccal compact. The main effects and interaction terms was quantitatively evaluated by quadratic model. The decrease in MT release was observed with an increase in both the formulation variables and as the carbopol: HPMC ratio increases the bioadhesive strength also increases. The desirability function was used to optimize the response variables, each having a different target and the observed responses were highly agreed with experimental values. The results demonstrate the feasibility of the model in the development of three layered buccal compact containing highly water-soluble drug MT.