Preparation of Mucoadhesive Patches for Buccal Administration of Metoprolol Succinate: In Vitro and In Vivo Drug Release and Bioadhesion

Purpose: To develop mucoadhesive patches for buccal administration of metoprolol succinate and to evaluate their in vitro and in vivo bioadhesion.
Methods: The mucoadhesive buccal patches were prepared by solvent casting technique using two different mucoadhesive polymers. The formulations were tested for in vitro drug permeation studies, buccal absorption, in vitro drug release studies, moisture absorption as well as for in vitro and in vivo bioadhesion.
Results: The peak detachment force and work of adhesion for MC5 (sodium carboxymethylcellulose, i.e., Na CMC) patch were 0.87 N and 0.451 mJ respectively and the corresponding values for CH5 (chitosan) were 5.15N and 0.987 mJ. Formulation CH5 (prepared with chitosan) showed 67.1 % release, while MC5 (Na CMC) showed drug release of 81.9 % in 6 h. Basic pharmacokinetic parameters such as Cmax, Tmax and AUCtotal varied statistically (p<0.05) when given by the buccal route compared with that of the solution given by the oral route.
Conclusion: The results indicate that formulation of suitable bioadhesive buccal patches with the desired permeability is feasible. The development of bioadhesive buccal formulation for metoprolol succinate with a lower dose and few side effects may be attainable.

Keywords
Mucoadhesive, Buccal patches, Metoprolol succinate, Sodium carboxymethylcellulose, Chitosan, Bioavailability