Recent developments in manufacturing emulsions and particulate products using membranes

Abstract

Membrane emulsification is a relatively new technique for the highly controlled production of particulates. This review focuses on the recent developments in this area, ranging from the production of simple oil-in-water (O/W) or water-in-oil (W/O) emulsions to multiple emulsions of different types, solid-in-oil-in-water (S/O/W) dispersions, coherent solids (silica particles, solid lipid microspheres, solder metal powder), and structured solids (solid lipid microcarriers, gel microbeads, polymeric microspheres, core-shell microcapsules and hollow polymeric microparticles). Other emerging technologies that extend the capabilities into different membrane materials and operation methods (such as rotating membranes, repeated membrane extrusion of coarsely pre-emulsified feeds) are introduced. The results of experimental work carried out by cited researchers in the field together with those of the current authors are presented in a tabular form in a rigorous and systematic manner. These demonstrate a wide range of products that can be manufactured using different membrane approaches. Opportunities for creation of new and novel entities are highlighted for low throughput applications (medical diagnostics, healthcare) and for large scale productions (consumer and personal products).

Manufacture of large uniform droplets using rotating membrane emulsification

“…The typical coefficients of variation CV 1 of droplet sizes in the direct emulsification using porous glass membranes in crossflow or stirring systems are in the range of 7-20 % and the mean droplet sizes range from less than 1 µm to over 60 µm [15]. The typical CV values in microchannel emulsification are less than 5 % and the mean droplet sizes range from several microns to 100 µm [19].…”

“…Several single-drop technologies have been developed for generating uniform droplets, such as injection of liquid through a capillary into another co-flowing immiscible fluid [3,4], penetration of dispersed phase through microfabricated parallel silicon channels [5] or interconnected channel network in microfluidic devices [6,7], and injection of dispersed phase through microporous membranes of different nature (glass, ceramic, metallic, polymeric) [8][9][10][11][12][13][14]. Production of various particulate products, such as microspheres and microcapsules, using membrane emulsification routes was recently reviewed by Vladisavljević and Williams [15].…”

pH-Sensitive Micelles for Targeted Drug Delivery Prepared Using a Novel Membrane Contactor Method

“…Membranes are increasingly used for fabrication of emulsions and particles 20 including nanoparticles such as solid lipid nanoparticles, 21 liposomes, 22 and nanoemulsions. 23 However, to the best of our knowledge, fabrication of micelles by dispersion through a microporous membrane has never been reported.…”

Porous polymer particles—A comprehensive guide to synthesis, characterization, functionalization and applications

“…Moreover, researchers developed microchannel emulsification for which every hole (channel) for discrete phase droplet formation is custom made. Silicon [115][116][117][118], metal [119][120] and polymer [121][122] based highly uniform microchannels have been used for monodisperse (CV <5%) particle manufacture [123]. The difference between membrane and microchannel emulsification is the fabrication of the emulsification material, which in turn affects the pore size distribution.…”