(42a) On Designing Functional Microparticles for Encapsulation and Controlled Release

The talk will provide an overview on some the research conducted at the Monash Advanced Particle Engineering Laboratory (http://www.mapelab.com/home.asp) and the Biotechnology and Food Engineering Group (BFE). The research group at Monash University utilizes a microfluidic drying approach to generate uniform microparticles with tightly controlled characteristics and sizes in a scalable, almost waste-free process. Microparticles of different materials with tailor-made properties and functionalities could be produced for encapsulation and controlled release. The effects of formulation (pH, concentration, dopants, solvents) and process parameters (droplet size, drying time) on microstructural properties and controlled release functionalities were investigated for silica-based and polymer-based microencapsulates. The ability to control the drug release kinetics of polymeric microparticles by manipulating their microstructures was demonstrated using polymeric aqueous dispersions Eudragit® RS and Eudragit® NE as matrix materials. The microstructures of particles and corresponding drug release mechanisms could be tuned by different blending strategies, such as the incorporation of highly hydrophilic ingredients (e.g. lactose) to accelerate release, or by using alginate or acid-hydrolysed tetraethyl orthosilicate (TEOS) as an additional barrier in the matrix. Microstructures with defined core-shell structures were spray dried using Eudragit® RS /silica system. The uniform core-shell microencapsulates with different shell thickness were assembled in a single step from a homogenous precursor, illustrating the ability to tailor particle structures and release rates of the active ingredient. Other examples including microencapsulation of curcumin, DHA, and astaxanthin using dairy-based proteins.

The ability to produce highly uniform particles with this unique approach has contributed to the understanding of how particles with different microstructures are formed, and how the physicochemical properties are related to their functionality. The underlying principles of particle formation mechanisms are applicable for other functional particles including mesoporous and magnetic particles. The strategy is useful for designing spray-dried particles of targeted properties in a scalable manner using multi-nozzles microfluidic dryer (to generate uniform particles), or with a conventional spray dryer.