(580g) Drug Encapsulation in Polymer Carriers Using Confined Impinging Jets and Vortex Mixers

This project focuses on the encapsulation of hydrophobic drugs based on diblock copolymer-arrested nucleation and growth of drug nanoparticles. Amphiphilic diblock copolymers dissolved in a good solvent can form micelles when the solvent quality for one block is decreased. Rapid mixing via a Confined Impinging Jets (CIJ) mixer achieves such a solvent quality change. The CIJ mixer consists of a confined volume chamber where one jet stream containing the diblock copolymer and drug dissolved in a water-miscible solvent is collided at high velocity against another jet stream containing water, an anti-solvent for the drug and the hydrophobic block of the copolymer. The fast mixing provides timescales that are shorter than the timescale for nucleation and growth of particles, which leads to the formation of nanoparticles with drug loading contents and size distributions not provided by other technologies. A tangential flow mixing cell allowing for various solvent: non-solvent ratios and leading to higher supersaturation levels was also used. Using the CIJ and tangential flow mixers, â-carotene was encapsulated in poly(styrene-b-ethylene glycol) (1,000-b-3,000 g/mole) nanoparticles, and the cancer drug paclitaxel in poly(å-caprolactone-b-ethylene glycol) (2,900-b-5,000 g/mole) and poly(å-caprolactone) (Mw=1,250 g/mole) homopolymer nanoparticles, all having diameters smaller than 90 nm, as determined by Dynamic Light Scattering. The particle size can be varied between 80 and 450 nm by varying the drug concentration or the homopolymer molecular weight. Current effort focuses on stabilizing the drug nanoparticles and controlling the in-vitro and in-vivo release of encapsulated drug.