Enhanced Drug Delivery; Bilayer Mucoadhesive Films for Oral Mucosa Disorders

Objectives: The buccal mucosa presents an attractive route for drug delivery due to its rapid absorption capabilities and potential for controlled drug release. Novel bilayer mucoadhesive buccal films loaded with triamcinolone acetonide (TA) were developed for treating topical of oral mucosa disorders. The permeability of TA through a biomimetic membrane, Permeapad™, was evaluated, and the impact of film composition and the presence of an ethyl cellulose (EC) backing layer on drug permeability was assessed.
Methods: Solvent casting method was employed to fabricate mucoadhesive monolayer (control) and bilayer (with EC) films made from hydroxypropyl methylcellulose (HPMC-K4M or K15M), polyvinylpyrrolidone (PVP); 2%w/w, and propylene glycol (PG-plasticizer, 1%w/w) containing TA (1%w/w). Drug permeability via a Permeapad™ barrier, simulating buccal mucosa, was assessed using a Franz diffusion cell with a donor-compartment simulating the oral cavity and a receptor-compartment representing systemic circulation.
Results: TA loaded HPMC-K4M film significantly improved the drug’s permeability (receptor- compartment), compared to TA-solution alone (from 8.54% TA-solution to 21.58% film), attributed to the synergy effect of HPMC and PG acting as a penetration enhancer. Films containing HPMC-K4M displayed higher drug permeability (receptor-compartment; 21.58%) than those with HPMC-K15M (17.05%), due to differences in gel layer formation and viscosity. PVP enhanced drug permeability (27.55%) by promoting quick hydration and improved adhesion to the Permeapad™ membrane. The impermeable EC backing layer significantly increased drug permeability by controlling unidirectional drug release and reducing drug loss into the donor-compartment (eg HPMC-K4M ~28%-monolayer film to ~10%-bilayer film). HPMC-K4M bilayer film offered the highest drug retention within the Permeapad™ barrier (45.78%), making it an optimal choice for topical treatment of oral infections.
Conclusions: Successfully developed mucoadhesive bilayer buccal films containing triamcinolone acetonide, demonstrated improved drug permeability, with HPMC-K4M bilayer film showing the highest drug retention. These findings hold promise for the effective topical treatment of oral mucosa disorders.