Complementary Effects of Porosigen and Stabilizer on the Structure of Hollow Porous Poly(lactic-co-glycolic acid) Microparticles

Poly(lactic-co-glycolic acid) (PLGA) plays a pivotal role in both conventional and emerging drug delivery applications. In this paper, we utilize a facile synthesis strategy to fabricate PLGA microparticles with shapes including the conventional hollow sphere and exotic shapes such as multicavity particles and cage-like particles. These shapes are obtainable at sizes between 0.6 and 6 μm in diameter. Electron microscopy images indicated the presence of water droplets in the oil phase of the emulsion, suggesting that excess salinity in the aqueous core facilitated water permeation from the bulk aqueous solution through the organic layer. These aqueous droplets in the oil phase later become the pores and surface cavities on the particles. Using Rhodamine B as a model drug, we measured both loading efficiencies and payload release profiles for all PLGA formulations and indicated a correlation between particle shape and drug release mechanism. Our report elucidates the roles of stabilizers and porosigens on the control of both size and shape of PLGA microparticles, providing a simple framework to produce a wide range of loadable PLGA microparticles with exotic shapes.