Preparation of polylactide microcapsules at a high throughput with a packed‐bed premix emulsification system

Abstract

Core–shell polymer microcapsules are well known for their biomedical applications as drug carriers when they are filled with drugs and gas‐filled microcapsules that can be used as ultrasound contrast agents. The properties of microcapsules are strongly dependent on their size (distribution); therefore, equipment that allows the preparation of small and well‐defined microcapsules is of great practical relevance. In this study, we made polylactide microcapsules with a packed‐bed premix emulsification system that previously gave good results for regular emulsions. Here, we tested it for applicability to a system in which droplets shrank and solidified to obtain capsules. The packed‐bed column was loaded with glass beads of different sizes (30–90 µm) at various bed heights (2–20 mm), and coarse emulsions consisting of the polymer, a solvent, and a nonsolvent were pushed repeatedly through this system at selected applied pressures (1–4 bar). The obtained transmembrane fluxes (100–1000 m3 m−2 h−1) were much higher than those recorded for other membrane emulsification techniques. The average size of the obtained microcapsules ranged between 2 and 8 µm, with an average span of about 1; interestingly, the capsules were 2–10 times smaller than the interstitial voids of the beds. The droplets were larger when we used thicker beds and larger glass beads, and these effect correlated with the pore Reynolds number (Rep). Two breakup mechanisms were identified: spontaneous droplet snap‐off dominated the system at low Reps, and localized shear forces dominated the system at higher Rep. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43536.

Black Soldier Fly (Hermetia illucens) Protein Concentrates as a Sustainable Source to Stabilize O/W Emulsions Produced by a Low-Energy High-Throughput Emulsification Technology

“…The effect of the viscosity of the continuous phase on the flux for the DMTS system has been previously seen by Kaade et al [ 31 ], who reported higher fluxes during the emulsification of LO emulsions stabilized with 2 wt.% Tween 20 than the ones obtained using 1% WPI. Moreover, proteins and other compounds in BSFPC stabilized emulsions can also result in fouling of the DMTS system, compared to emulsions stabilized with WPI as already observed during premix emulsification with several microstructured systems [ 31 , 61 , 62 , 63 ].…”

Droplet breakup mechanisms in premix membrane emulsification and related microfluidic channels

“…This represents a very simple and inexpensive approach wherein packed bed of different interstitial voids and thicknesses can be easily established to achieve desirable hydrodynamic conditions. The packed bed system has found useful applications in the production of protein stabilized emulsions [70], double emulsions [71,72], microcapsules [73], and foams [74]. The future research in this field could focus on particles of different materials and shapes, to construct packed bed of different properties.…”

Chemical and Process Engineering

“…Dynamic membranes have proven to be a robust alternative to conventional membranes. Experimental studies conducted to date have been concerned with the application of hydrophilic dynamic membranes consisting of glass beads (Eisinaite et al, 2016;Kaade et al, 2020;Ladjal Ettoumi et al, 2017;Laouini et al, 2014;Nazir et al, 2013;Sahin et al, 2014;Sawalha et al, 2016;van der Zwan et al, 2008;Wang et al, 2021a;2021b;. No reports have been found on the preparation of w/o emulsions, the use of hydrophobic membranes, and the application of non-spherical particles.…”