Weaving colloidal webs around droplets: spontaneous assembly of extended colloidal networks encasing microfluidic droplet ensembles

Microfluidics-enabled particle engineering of monodisperse solid lipid microparticles with uniform drug loading and diverse solid-state outcomes

Lipids serve as excellent excipients for drug products. Solid lipid microparticles (SLMs) are relatively underexplored in drug delivery; these particles are conventionally prepared using processes yielding polydisperse size distributions, such as spray congealing or emulsification. In this paper, we demonstrate a microfluidics-enabled process for particle engineering of monodisperse solid lipid microparticles with size and content uniformity. To overcome low solubility, we use a volatile solvent to increase drug loading, making the drug-lipid solution a single phase, enabling identical drug loading across particles. We use microfluidic flow extrusion of the solution to generate uniform drug-loaded SLMs, substantially enhancing monodispersity. This method generalises across three drugs-ibuprofen, 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY), and naproxen, and two lipids-beeswax and hard fat (Suppocire NAI 25A), forming particles of various solid states: amorphous naproxen in crystalline lipids, crystalline ROY in crystalline lipids, and a eutectic mixture of ibuprofen-hard fat. In vitro dissolution studies on the ibuprofen-hard fat SLMs reveal gradual release, fitting the Higuchi model with 50-65% drug released over 72 h. This work expands the drug particle engineering toolbox to enable the formulation of SLMs with high precision in particle size and drug loading. Moreover, the diverse solid-state outcomes enabled by our method makes it applicable to various drugs having different formulation requirements (crystalline/amorphous).

Droplet-Templated Antisolvent Spherical Crystallization of Hydrophilic and Hydrophobic Drugs with an in situ Formed Binder

This study presents a novel droplet-templated antisolvent spherical crystallization method applicable to both hydrophilic and hydrophobic drugs. In both cases, an alginate hydrogel binder forms in situ, concurrently with the crystallization process, effectively binding the drug crystals into monodisperse spheres. This study presents a detailed process description with mass transfer modeling, and with characterization of the obtained alginate/drug spheres in terms of morphology, composition, and drug loading. Although glycine and carbamazepine are used as model hydrophilic and hydrophobic drugs, this method is easily generalized to other drugs, and offers several benefits such as minimal thermal impact, fast crystallization rates, high drug-binder loading ratios, and high selectivity toward metastable polymorphs.