COLL 448 |
| R. K. Prud'homme1, Brian K. Johnson2, and Walid Saad2. (1) Princeton U, Dept. of Chemical Engineering, Princeton, NJ 08544-5263, (2) Department of Chemical Engineering, Princeton University, Princeton, NJ 08544 |
| Organic pharmaceuticals, which are poorly water soluble, have limited bioavailability when formulated as powders in the standard size range of 10-100 m. We demonstrate the new process of impinging jet precipitation with block copolymer stabilization on -carotene which is metabolized to vitamin A. The impinging jet process allows the production of nano-particles by: 1) elimination of mass transfer limitations and compositional gradients within 10 ms as determined by independent measurements with competitive-parallel reactions, 2) production of high supersaturations and solute concentrations so that high production rates can be obtained, and 3) control of particle size by stabilization of the particle using block copolymer self-assembly. The process depends critically on control of three time scales: particle nucleation and growth, block copolymer micellization, and polymer adsorption on the particle to produce steric stabilization. We present data on characterization of the mixing times using competitive reactions, data on polymer micellization kinetics, and results on the successful production of -carotene particles with control of the particle size between 0.1 m to 2 m. Homogeneous rapid nucleation and growth produces particle size distributions that are much narrower than those obtained by alternate size-reduction or precipitation routes. |
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Nanoscience and Nanotechnology
2:00 PM-5:15 PM, Wednesday, March 31, 2004 Marriott -- Orange County 5, Oral
Division of Colloid and Surface Chemistry |