Polyelectrolyte Stabilized Drug Nanoparticles via Flash Nanoprecipitation: A Model Study With β-Carotene

Polyelectrolyte protected β-carotene nanoparticles (nanosuspensions) with average diameter of < 100 nm were achieved by turbulent mixing and flash nanoprecipitation (FNP). Three types of multi-amine functional polyelectrolytes, ε-polylysine (ε-PL), poly(ethylene imine) (PEI), and chitosan, were investigated to electrosterically protect the nanoparticles. Particle size and distribution were measured by dynamic light scattering (DLS); particles were imaged via scanning electron microscopy (SEM) and cryogenic transmission electron microscopy (cryo-TEM). Low pH and high polyelectrolyte molecular weight gave the smallest and most stable particles. High drug loading capacity, > 80 wt%, was achieved by using either PEI or chitosan. X-ray diffraction (XRD) patterns showed that β-carotene nanoparticles were amorphous. These findings open the way for utilization of FNP for preparation of nanoparticles with enhanced bioavailability for highly water insoluble drugs.