Abstract
Sea buckthorn oil (Hippophae rhamnoides L.) is medically used both externally and internally, but the external application is unsuitable due to its liquid, lipophilic and highly coloured nature. These difficulties could be overcome by a formulation of semisolid emulsion with sea buckthorn oil. Previous research on this formulation showed that it has higher wound healing potential than sea buckthorn oil, possessing an enhanced structure of liquid crystals, stability and suitability for topical use.
The aim of this investigation was to completely characterizise a proposed emulsion by testing skin effects, such as moisturising potential, skin pH and potential to cause skin irritation.
The emulsion was prepared by standard emulsifying techniques using a combination of surfactants that form an enhanced structure of liquid crystals. Approximately 40% of sea buckthorn oil was incorporated. The moisturising potential and skin pH were tested on the healthy skin of volunteers. Skin tolerance was tested on a rabbit skin model and evaluated by the Draize test.
The tested emulsion containing sea buckthorn oil did not cause a significant change in skin pH, while it significantly increased skin hydration. Th ere was an absence of edema or erythema type of irritation after 2 h, 24 h, 48 h, 72 h and 7 days of application of the emulsion with sea buckthorn oil.
The tested formulation shows good moisturizising effects and does not cause human or animal skin irritation. Th e study confi ms that the combination of the proposed ingredients in a sea buckthorn oil emulsion is adequate and could be safe for skin application