Synthesis and dethreading kinetics of pH-sensitive α-cyclodextrin - polyethylene glycol polyrotaxanes bearing cleavable endcaps

COLL 53

David H. Thompson, davethom@purdue.edu1, Scott Loethen1, Tooru Ooya, ooya@jaist.ac.jp2, and Nobuhiko Yui2. (1) Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, (2) School of Materials Science, Japan Institute of Science and Technology, 1-1 Asahidai, Tatsunokuchi, Ishikawa, 923-1292, Japan
Two α-cyclodextrin-polyethylene glycol (α-CD - PEG1500) polyrotaxanes with endcapping groups that were installed using Cu(I)-catalyzed Huisgen cyclization have been synthesized and their acid-catalyzed degradation kinetics characterized. Dethreading rates upon exposure to mild deprotection conditions were monitored by turbidity and GPC analysis. The vinyl ether endcapped polyrotaxanes are stable at pH 7 for 16 h, but are solubilized at approximately 0.0211 min-1 at pH 4. Our results show that pH-triggerable polyrotaxanes can be readily and efficiently prepared from polypseudorotaxanes in high yield by Huisgen cyclization of azido- and alkynyl-modified precursors in the presence of Cu(I). Potential utilization of these materials in drug delivery applications will be briefly discussed.
 

Advances in Nanomedicine
8:30 AM-12:20 PM, Sunday, 10 September 2006 Sir Francis Drake -- Monterey/Cypress Rooms, Oral

Division of Colloid & Surface Chemistry

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