(527f) On Single Step Assembly of Uniform Core-Shell Microparticles with Tunable Controlled Release Functionalities

Core/shell
microparticles are of interest for various
applications including pharmaceutical engineering, due to the possibility of
fine-tuning individual functionalities of the different parts. Here we report a
new approach for continuous and scalable production of core/shell
microparticles, using acrylic nanoparticles (Eudragit¨ RS) as the shell, and
hydrolized tetraethyl orthosilicate (TEOS) forming the silica core upon the
single-step assembly. The method is capable of forming monodisperse microparticles
from homogeneous precursors without the use of any organic solvents. Precise
control of particle uniformity is realized via the use of a micro-fluidic spray
drying technique, which has been previously demonstrated to generate
monodisperse chitosan microparticles of specific sizes [1] and polymeric
microparticles for controlled drug release applications [2]. Evaporation
induced self-assembly during spray drying is utilized to manipulate the spatial
configuration of the particles, including shell thickness. Control over the shell
thickness can be directly achieved from the ratio of ingredients in the
precursors. A fluorescent compound, Rhodamine B, is used as a highly
water-soluble model drug to investigate the controlled release properties of
these microparticles, with the release behaviors shown to be significantly
dependent on the microstructural properties.

A schematic diagram of particle formation due to
evaporation induced self-assembly during spray drying, with FESEM images of (A)
monodisperse spray dried microparticles with average diameter of 55 mm, with
(B) cross-section displaying core-shell configuration (inset scale bar: 1µm).

References:

1.   
Liu, W., Wu, W., Selomulya, C., Chen, X. D., 2011,
Uniform Chitosan Microparticles Prepared by a Novel Spray-Drying Technique, International Journal of Chemical Engineering,
doi:10.1155/2011/267218

2.   
Liu, W., Wu, W., Selomulya, C., Chen, X. D., 2011, A
single step assembly of uniform microparticles for controlled release
applications, Soft Matter,
DOI:10.1039/C0SM01371D.