Novel acyclovir-loaded film-forming gel with enhanced mechanical properties and skin permeability

To develop a novel acyclovir (ACV)-loaded film-forming gel (FFG) with the advantage of providing skin protection and continuous drug release upon application, various FFGs and FFG-films were prepared using drug, chitosan, hydrophilic polymer, plasticizer, lactic acid, water, and ethanol. The mechanical and physiochemical properties were evaluated by film formation time, tensile strength, break elongation, Young's modulus, SEM, FTIR, DSC, and XRD. To identify skin permeation of drug, in vitro skin permeation study was conducted with a Franz diffusion cell using dorsal skin of SD-rat. The ACV-loaded FFG consist of ACV/chitosan/PVP/PEG600/lactic acid/water/ethanol at the weight ratio of 1/1.5/0.5/3/2/40/60 exhibited rapid film formation within about 5 min, resulting in rapid film formation. Furthermore, this ACV-loaded FFG film provided excellent flexibility and showed a low degree of drug crystallization as a result of physicochemical properties evaluation. The ACV-loaded FFG with a high ratio of PEG600 showed a high skin permeability compared to other formulations and significantly improved skin permeability compared to commercial products. Consequently, this novel ACV-loaded FFG would be an effective pharmaceutical product with excellent mechanical properties and skin permeability for herpes labialis.