The use of 0.2 μm or 0.22 μm filters may not always be possible if the NPs are larger than, or close to, the pore size of the filters since clogging can occur resulting in a decreased yield. 10,11 For example, filtration of 200-300 nm poly(dl-lactide-co-glycolide) (PLGA) nanospheres prepared using the standard Emulsion Solvent Diffusion (ESD