Enhancing Permeability of Acyclovir from Mucoadhesive Buccal films Utilizing Herbal Bioenhancers: An in vitro Investigation

Background: Acyclovir is a widely used anti-viral drug that has low bioavailability when administered orally and is also difficult to administer parenterally due to its inherent solubility limitations. Buccal administration of Acyclovir with the aid of absorption enhancers can improve the permeability of the poorly permeable anti-viral drug. Materials and Methods: Acyclovir-loaded buccal films were prepared by solvent casting method using piperine or zingiberene as herbal bioenhancers. The films were characterized for weight, thickness, folding endurance, surface pH, drug content, swelling index, tensile strength, mucoadhesion time and mucoadhesive strength. They were also evaluated for in vitro drug release and ex vivo permeation using porcine mucosa. Results: The buccal films were found to be smooth and elegant with thicknesses ranging from 0.13 mm to 0.16 mm indicating the uniformity in thickness among the films. All the formulated films demonstrated excellent folding endurance of more than 200 and also the tensile strength ranged from 0.8 kg/cm2 to 3.33 kg/cm2 indicating the robustness of the buccal films. Ex vivo mucoadhesion studies revealed that the films had a mucoadhesion time of more than 100 min. In vitro drug release showed that films released the drug in a prolonged manner for more than 350 min due to the presence of chitosan in the formulation. The drug permeation from all the piperine and zingiberene-incorporated buccal films was found to be more than two-fold compared to those without the permeation enhancers. Conclusion: Acyclovir loaded buccal films containing bioenhancers were able to successfully permeate the buccal mucosa thus achieves better bioavailability.