One-step fabrication of triple-layered polymeric microparticles with layer localization of drugs as a novel drug-delivery system
Lee, Wei Li
Loo, Say Chye Joachim
Date of Issue2010
School of Materials Science and Engineering
Particulate systems have tremendous potential to achieve controlled release and targeted delivery of drugs. However, conventional single-layered particles have several inherent limitations, including initial burst release, the inability to provide zero-order release, and a lack of time-delayed or pulsatile release of therapeutic agents. Multi-layered particles have the potential to overcome these disadvantages. Here we show for the first time how triple-layered polymeric microparticles can be fabricated through a simple, economical, reliable, and versatile one-step solvent evaporation technique. Particle morphologies and layer configurations are determined using scanning electron microscopy (SEM), polymer dissolution tests, and Raman mapping. Key fabrication parameters that affect the formation of triple-layered polymeric microparticles comprising of poly(D,L-lactide-coglycolide, 50:50) (PLGA), poly(L-lactide) (PLLA) and poly(ethylene-co-vinyl acetate, 40 wt% vinyl acetate) (EVA) will be discussed, along with their formation mechanisms. Layer thickness and the configurations of these microparticles were found to be altered by changing the polymer mass ratios. Finally, it was shown that drugs can be localized in specific layers of the microparticles. This fabrication process can therefore be used to tailor microparticle designs, allowing such “designer” particulate drug delivery systems to function across a wide range of applications.
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.