Well defined NIPAAm-acrylic block copolymers: Materials that form nano-sized structures for controlled drug delivery

PMSE 99

Angel Licea-Claverie, aliceac@tectijuana.mx1, Sergio Carrion-Garcia1, Maria del Rosario Medina-Urquiza1, Jose M. Cornejo-Bravo2, Craig J. Hawker3, and Curt W. Frank4. (1) Centro de Graduados e Investigación, Instituto Tecnológico de Tijuana, A.P. 1166, 22000 Tijuana, B.C, Mexico, (2) Facultad de Ciencias Quimicas e Ingenieria, Universidad Autonoma de Baja California, Calzada Tecnologico 14418, Mesa de Otay, 22300 Tijuana, B.C, Mexico, (3) Materials Research Laboratory, University of California at Santa Barbara, Santa Barbara, CA 93106, (4) Department of Chemical Engineering, Stanford University, Stanford, CA 94350
Poly(N-Isopropylacrylamide) (PNIPAAm) is an attractive polymer due to its temperature-driven volume phase-transition at 32oC. This behavior can be fine-tuned by copolymerizing NIPAAm with other monomers. A poorly addressed issue is the fact that most NIPAAm-copolymers are prepared by traditional free radical polymerization, lacking control on molecular weight, molecular weight distribution and composition. Using Nitroxide mediated controlled free-radical polymerization (Nox-CFRP) a series of temperature- and pH-sensitive block-copolymers based on NIPAAm and acrylic comonomers were prepared controlling their size and composition. Some copolymers showed the ability to self-organize into micelle-like nano-structures under specific pH- and temperature conditions. The temperature driven change from hydrophilic to hydrophobic in the NIPAAm-units yields the destruction of the micelle-like structures; a behavior that was exploited for controlled drug delivery. Block copolymers containing acrylic acid units were loaded with basic hydrophobic drugs. Release of this drugs triggered by changes in temperature, pH and ionic strength was demonstrated.
 

Block Copolymers as Nanoscale Materials
8:00 AM-11:20 AM, Monday, 11 September 2006 San Francisco Marriott -- Salon 7, Oral

Division of Polymeric Materials: Science & Engineering

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006