Polymeric and electrospun patches for drug delivery through buccal route: Formulation and biointerface evaluation

Introduction: Of the various transmucosal routes which are being considered for extended and controlled drug delivery, buccal route is superior to other methods owing to high administrability and milder environment for drug absorption. In this direction, mucoadhesive buccal films of venlafaxine were fabricated using a combination of biocompatible polymers. Aim: The main objective of the study was to standardize an optimized formulation of polyvinyl alcohol, sodium carboxymethyl cellulose and sodium alginate that would lead to sustained drug delivery in the form of buccal patches. Methods: Varying polymeric concentrations were utilized for the fabrication of buccal patches via solvent casting method. The physical parameters were evaluated, followed by in vitro drug release studies. The electrospun nanofibers were prepared for optimized formulations and the buccal delivery system was compared to oral and intravenous routes for absorption, distribution, and elimination during in vivo studies using venlaflaxine. Results: The patches had high tensile strength with uniform drug content and surface pH in the range of 6.28-6.88. The release of drug was steady with a maximum release of 89.97% at 5 h. The negative hemolytic and cytotoxicity studies with TR146 cells over a range of concentrations indicated biocompatibility of the mucoadhesive patch with human tissues. The pharmacokinetics of the buccal patch of the radiolabeled drug, Tc-99m-venlaflaxine, displayed favorable release pattern. The radiolabeled patch attached to rabbit buccal mucosa displayed high retention with controlled drug release as indicated by the C-max and T-1/2 values (19.94 ng/ml and 3 h). The drug release mechanism corresponded to a pure fickian diffusion-controlled mechanism following Higuchi's model. Electrospun fibrous patch of the drug had a 10% higher drug release than solvent cast patch. Conclusion: In vitro and in vivo data indicate that the polymeric system was successfully optimized for sustained drug release for about 5 h in a continuous manner with electrospun fibrous patch showing 10% increase in drug release studies. The patches displayed ideal physical and biocompatibility characteristics. This polymeric combination can therefore be further utilized for development of novel drug delivery systems with sustained drug release pattern.