Crystallized miniemulsions: Influence of operating parameters during high-pressure homogenization on size and shape of particles

Miniemulsions were produced by high-pressure homogenization at 80 °C. Triglyceride oil, trimyristin, tripalmitin and propylene glycol monostearate were applied as dispersed phases. Tween 80 was used as emulsifier. Cooling down of tripalmitin and propylene glycol monostearate dispersions to room temperature induced crystallization of the lipid. Trimyristin dispersions required a cooling to 4–8 °C for crystallization of the lipid. Dispersed triacylglyceride oil stays liquid at any investigated temperature. Additionally nanostructured lipid carriers – which were two-phase particles with liquid oil and solid lipid – were produced. These particles feature potential increase of loading capacity compared to one-phase particles for actives. The dispersions were characterized by dynamic light scattering, electron microscopy, differential scanning calorimetry and small angle X-ray scattering. Differences between solid and liquid particles are shown and discussed. The influence of the operating parameters homogenization pressure and residence time were studied. The dynamic viscosities of the oil and melts were measured in the same range. The interfacial tensions between triglyceride oil and the Tween 80 solution as well as trimyristin and Tween 80 solutions were measured.