Efficiency of emulsifier-free emulsions and emulsions containing rapeseed lecithin as delivery systems for vectorization and release of coenzyme Q10: physico-chemical properties and in vitro evaluation

To improve the encapsulation and release of coenzyme Q(10) (CoQ(10)), emulsifier-free-emulsions were developed with a new emulsification process using high-frequency ultrasound (HFU) at 1.7 MHz. Nano emulsions containing CoQw were prepared with or without rapeseed lecithin as an emulsifier. The emulsions prepared with HFU were compared with an emulsion of CoQ(10) containing emulsifier prepared with the same emulsification technique as well as with emulsions prepared with low-frequency ultrasound coupled with high-pressure homogenization (LFU+HPH). The physico-chemical properties of the emulsions were determined by average droplet size measurement with nano-droplet tracking analysis, droplet surface charge with zeta potential measurement, surface tension and rheological behaviour. Emulsions made by LFU+HPH with an emulsifier showed lower droplet sizes due to cavitation generated by the HFU process. Surface tension results showed that there was no significant difference between emulsions containing lecithin emulsifier regardless of the preparation process or the inclusion of CoQ(10). In vitro biocompatibility tests were performed on human mesenchymal stem cells in order to show the cytotoxicity of various formulations and the efficiency of CoQ(10) loaded emulsions. In vitro tests proved that the vectors were not toxic. Furthermore, CoQ(10) facilitated a high rate of cell proliferation and metabolic activity especially when in an emulsifier-free formulation. (C) 2016 Elsevier B.V. All rights reserved.