Betulin Emulsion Preparation by High-Speed Homogenization

Betulin obtained from Pro development Ltd. (Yekaterinburg, Russia) was prepared as an emulsion, as described by Zavorokhina et al. [50 (link)], with modifications using a high-speed homogenization technique. Betulin was dissolved in a solution of ethanol and glycerol (70:30 at 20 °C) under continuous stirring at 500 rpm and 70 °C for 20 min until thoroughly mixed. The resulting mixture was heated to 40 °C to distill off the ethanol. A betulin solution was introduced dropwise to the external phase containing sodium chloride and an emulsifier, using a flow microreactor (Mr–Lab–VS, Elsoff, Germany) at a feed rate of 0.1 mL/min. The mixture was then heated to 70°C and intensively mixed using an IKA dispersant (T10 basic Ultra–TURRAX, Staufen, Germany).