Bacterial nanocellulose patches as a carrier for hydrating formulations to improve the topical treatment of nail diseases.

Bacterial nanocellulose has been widely investigated for wound healing applications, mainly due to its moisturizing capabilities and biocompatibility. Even though the topical therapy of nail diseases could benefit from these properties, this application has not yet been investigated. Therefore, actively hydrating nail patches based on bacterial nanocellulose were developed to improve the delivery of ciclopirox olamine and Boswellia serrata extract through the nail plate. The nanocellulose matrix was used to enable the application of hydration enhancing solutions based on glycerol and urea as a mechanically stable patch. While the favorable mechanical characteristics of the material remained unchanged, an increase of the incorporated glycerol concentration enhanced the transparency and wetting capacity of the patches. A biphasic drug release from the patches could be observed for drug and extract with a faster release for the hydrophilic ciclopirox olamine. High glycerol concentrations correlated with increased cumulative release and permeation through keratin films for drug and extract, demonstrating the hydration driven permeation enhancement. Patches containing ciclopirox olamine showed strong antimycotic effects against relevant pathogens for onychomycosis. The present finding proposed the combination of bacterial nanocellulose with glycerol, urea and different drug as a promising platform for the local treatment of nail diseases.

Development and characterization of bacterial nanocellulose loaded with Boswellia serrata extract containing nanoemulsions as natural dressing for skin diseases.

The combination of the anti-inflammatory lipophilic Boswellia serrata extract with the natural hydropolymer bacterial nanocellulose (BNC) for the treatment of skin diseases is counteracted by their different hydro/lipophilicity. To overcome the hydrophilicity of the BNC, the water in its network was exchanged by single and double nanoemulsions. Incorporation of the Boswellia serrata extract in the nanoemulsions formed particles of about 115 to 150 nm with negative zeta potential and storage stability over 30 days at temperatures between 4 and 32 °C. Their loading into the BNC did not change the preferential characteristics of the nanocellulose like water absorption and retention, softness, and pressure stability in a relevant way. Loaded BNC could be sterilized by an electron-beam procedure. A biphasic drug release profile of lead compounds was observed by Franz cell diffusion test. The biocompatibility of the loaded BNC was confirmed ex ovo by a shell-less hen's egg test. Tape stripping experiments using porcine skin determined a dependency of the drug penetration into skin on the type of nanoemulsion, single vs. repeated applications and the incubation time. In conclusion, the hydrophilicity of BNC could be overcome using nanoemulsions which offers the possibility for the anti-inflammatory skin treatment with Boswellia serrata extract.