The effect of type of organic phase solvents on the particle size of poly(d,l-lactide-co-glycolide) nanoparticles

Poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles were prepared by an emulsification-diffusion method. To investigate the effect of type of organic phase solvents on the mean particle sizes of obtained PLGA nanoparticles, different organic solvents [ethyl acetate (EA), propylene carbonate (PC), acetone (ACE), and dichloromethane (DCM)] were used with several stabilizers [didodecyl dimethyl ammonium bromide (DMAB), poly(vinyl alcohol) (PVA), and Pluronic F68]. The particle size of nanoparticles was observed by the dynamic light scattering method and atomic force microscopy (AFM). When DMAB, an ionic stabilizer, was used, small PLGA nanoparticles below 70 nm were obtained for EA and PC as partially water-soluble organic solvents, while large PLGA nanoparticles above 290 nm were prepared for ACE and DCM as a fully water-soluble solvent and a water-immiscible solvent, respectively. However, when PVA or Pluronic F68, non-ionic stabilizers, were used, a big difference in mean particle sizes between partially water-soluble solvent or fully water-soluble solvent and water-immiscible solvent was not observed, and all particles showed a large mean diameter above 110 nm, irrespective of the type of organic phase solvents.