An integrated buccal delivery system combining chitosan films impregnated with peptide loaded PEG-b-PLA nanoparticles

Peptide (insulin) loaded nanoparticles (NPs) have been embedded into buccal chitosan films (Ch-films-NPs). These films were produced by solvent casting and involved incorporating in chitosan gel (1.25% w/v), NPs-Insulin suspensions at three different concentrations (1, 3, and 5 mg of NPs per film) using glycerol as plasticiser. Film swelling and mucoadhesion were investigated using 0.01 M PBS at 37 °C and texture analyzer, respectively. Formulations containing 3 mg of NPs per film produced optimised films with excellent mucoadhesion and swelling properties. Dynamic laser scattering measurements showed that the erosion of the chitosan backbone controlled the release of NPs from the films, preceding in vitro drug (insulin) release from Ch-films-NPs after 6 h. Modulated release was observed with 70% of encapsulated insulin released after 360 h. The use of chitosan films yielded a 1.8-fold enhancement of ex vivo insulin permeation via EpiOral™ buccal tissue construct relative to the pure drug. Flux and apparent permeation coefficient of 0.1 μg/cm2/h and 4 × 10−2 cm2/h were respectively obtained for insulin released from Ch-films-NPs-3. Circular dichroism and FTIR spectroscopy demonstrated that the conformational structure of the model peptide drug (insulin) released from Ch-films-NPs was preserved during the formulation process.