Use of dynamic membranes for the preparation of vitamin E-loaded lipid particles: An alternative to prevent fouling observed in classical cross-flow emulsification

• Solid lipid particles preparation using a packed bed of glass beads was investigated.
• Fouling of dynamic membranes was studied.
• Premix emulsification process was compared to classical cross flow emulsification.

Solid lipid particles (SLP) were introduced at the beginning of the 1990s as an alternative to encapsulation systems such as emulsions and liposomes used in cosmetic and pharmaceutical preparations. The present paper investigated for the first time the preparation of SLP based on premix emulsification with packed beds of micron-sized glass beads. A coarse pre-emulsion was prepared by mixing the aqueous phase (water and Tween 80) and the lipid phase (Precirol and vitamin E) under magnetic stirring at 1200 rpm during 15 min, followed by passing the premix through the glass beads layer. SLP were formed by cooling to room temperature of the final emulsion.SLP were successfully produced under various conditions, but was most optimally carried out by extruding a coarse O/W emulsion 6 times under a pressure of 2 bar through a dynamic membrane. For example, when a 2 mm layer of glass beads sized 63 μm was used, the premix size of 5 μm was reduced to 1.5 μm. It was found that particle size tended to decrease with increasing feed pressure, increasing number of passes, decreasing glass bead size and decreasing bed height. Even more importantly, the dynamic membrane was hardly prone to fouling compared to the membranes used in traditional cross-flow emulsification which typically need small pore size for the production of particles of similar size. In addition, the small beads could be easily cleaned by disintegrating the bed. The preparation process developed was easy to use, easy to scale-up, and the particle size could be controlled by appropriate choice of process parameters.