Development of nanoemulgel system based on Opuntia ficus-indica (L.) seed oil and nanoclays: Formulation, characterization and application for wound treatment

Opuntia ficus-indica (L.) (OFI) seed oil, rich in bioactive compounds, exhibits antibacterial, antioxidant and healing properties suggesting its suitability in wounds treatment. However, its use is limited due to the high lipophilicity and potential irritancy. In order to exploit OFI seed oil potentialities in wound healing, the possibility of formulating it as nanoemulgel was considered. Nanoemulgel prototypes were prepared using a stable oil-in-water (O/W) nanoemulsion based on: OFI seed oil (10 % w/w) as internal phase, Tween® 80 (5 % w/w) as emulsifier and bidistilled water. The external water phase was viscosized by the addition of the clays like Laponite®, Pangel S9®, Cimsil G30® or Montmorillonite in order to promote both stability and performances. The nanoemulgels prepared deeply characterized in terms of dimensions, ζ-potential, pH value. The physical stability was evaluated both by a Turbiscan Lab apparatus over 35–40 days and by visual inspection by storing all samples at 25 °C for 28 days. The spreadabilty and rheological properties were studied as well. The formulation containing Laponite® 3 % w/w was identified as the most promising as showed the best characteristics mainly in terms of pH, spreadability and viscosity able to ensure easy application and likely therapeutic benefits. Further characterizations confirmed its antimicrobial activity against Gram-positive bacteria and excellent skin compatibility evaluated by Dermal Irritection® test. Thus, Laponite® OFI seed oil nanoemulgel could be considered a suitable, skin safe candidate for the treatment of Gram-positive bacteria skin infections e.g. in wound treatment.