The Effect of Processing Conditions on the Size and Polydispersity of Polymer Nanoparticles prepared with Impingement Jets Mixing

Biodegradable polymer nanoparticles are considered for controlled drug delivery because they are small enough to diffuse through tissues, target specific tissues, and penetrate through cell membranes to deliver drugs more locally, mitigating side effects seen with intravenous injection. There are still difficulties in producing polymer nanoparticles at scale and in a size range (60 nm to 80 nm in diameter) that are large enough to avoid many of the biological barriers and yet small enough to have reasonable diffusion rates through tissue. In this work, the effects of process parameters (Reynolds number, amount of surfactant, location of surfactant, quench volume, and solvent evaporation time) on the size and polydispersity index of polymer nanoparticles were investigated with the production of nanoparticles using solvent displacement method in a confined impingement jets mixer. Dynamic light scattering was used to determine the size and polydispersity index of the nanoparticles. Without surfactant, it was found that Reynolds number influenced the size and polydispersity index of the nanoparticles as the particles aggregated at high flow rates. The location of the surfactant with increasing Reynolds number and the concentration of surfactant in the aqueous phase did not have a significant effect on both the particle size and polydispersity. However, it was found that a quench solution was necessary to stabilize the nanoparticles, and having a high concentration of surfactant in the quench solution would decrease the size of the nanoparticles. Future work can be done to identify the long-term stability of these nanoparticles, find methods to purify them from the excess surfactant, and conduct drug release studies