Automated in-situ production of oil-in-water emulsions using the Temperature Adjustable Membrane Emulsification Device (TAMED)

The Temperature Adjustable Membrane Emulsification Device (TAMED) was developed and evaluated as an automated and temperature-controlled system for laboratory-scale membrane emulsification. The device replaces repeated manual syringe extrusion with an automated sequence in which two pneumatic piston pumps alternately force the batch volume through a syringe filter. Oil-in-water emulsions containing 3.5 vol% or 30 vol% medium chain triglyceride oil and stabilized with polysorbate 20 or polysorbate 80 were processed at 23 °C and 60 °C. 15 mL emulsion batches with uniform droplet sizes were produced by adding the oil and aqueous phases directly to the same syringe without prior premixing, and applying 20 passes through a composite membrane with a nominal pore size of 10 μm.
Increasing the number of passes progressively reduced the Sauter mean diameter and narrowed the droplet size distribution (span ≈ 1). After 20 passes, Sauter mean diameters of approximately 2.0–2.9 μm were obtained. Similar final droplet size distributions were observed with and without prior mixing. Both surfactants produced significantly smaller droplets at 60 °C than at 23 °C. ... mehrImportantly, this decrease occurred despite a lower transmembrane flux at 60 °C, indicating that the reduction in interfacial tension outweighed the opposing effects of the lower continuous-phase viscosity and transmembrane flux. Surfactant type and dispersed phase content also significantly affected the final droplet size. In addition, direction-dependent differences were observed in membrane resistance and transmembrane flux.
Within the investigated process and formulation range, TAMED enabled automated in-situ preparation and repeated extrusion of small emulsion volumes under defined temperature and cycle conditions. The device therefore provides a laboratory-scale platform for investigating the effects of process and formulation parameters on membrane emulsification.