Preparation of Uniform Nonspherical PLGA Particles in the Nanosize Range by Using a Two-Step Premix Membrane Emulsification Technique

However, spherical-shaped particles are usually produced by conventional emulsion-based methods due to the spontaneous minimization of interfacial tension. In our previous work, uniform nonspherical poly(lactic-<i>co</i>-glycolic acid) (PLGA) particles in the micro-size range were successfully prepared by a premix membrane emulsification technique with phosphate-buffered saline (PBS) as a deformation inducer.

However, it is difficult to produce nanosized nonspherical particles because of the inherent conflict between the reduction of droplet size and emulsion deformation. To overcome this limitation, a two-step premix membrane emulsification strategy was developed in the present study to temporally and spatially decouple emulsion formation from shape deformation. Through optimization employing one-variable-at-a-time (OVAT) and orthogonal experimental design, the influence of key formulation factors, including PLGA concentration, poly(vinyl alcohol) (PVA) concentration, PBS concentration, and oil phase volume, on the shape of the particles was systematically evaluated.