Unveiling the optimal path: High-pressure homogenization and D-phase emulsification methods for borage oil nanoemulsion design

Borage oil contains high levels of essential omega-6 fatty acids, which are important for skin structure and function. For this reason, this oil can be used for the treatment of cutaneous diseases including atopic dermatitis. This disease is associated with an abnormality in essential fatty acids (EFAs) metabolism, particularly in the production of gamma-linolenic acid, leading to impaired incorporation of EFAs into the phospholipid membrane. EFAs bioavailability can be enhanced by using a borage oil nano-based drug delivery system. In this study a borage oil nanoemulsion was prepared using high-pressure homogenization (HPH) and D-phase emulsification (DPE), respectively, high and low energy methods. A design space approach was performed to optimize the formulations. The optimized HPH nanoemulsion (HPH-NE) presented a particle size and zeta potential (ZP) of 425.3 +/- 5.6 nm, and - 19.4 +/- 3.7 mV, respectively. For the DPE nanoemulsion (DPE-NE) the particle size was 334.4 +/- 5.2 nm, and the zeta potential was - 34.6 +/- 1.0 mV. Furthermore, DPE-NE presented higher toxicity compared to HPH-NE, possibly related to the presence of the polyol. These nanoemulsions may improve the borage oil bioavailability for oral administration. Thus, they can be used as an adjuvant therapy in the treatment of atopic dermatitis.