Calander Home 2001-2002 2002-2003 May 13 - Ron Siegel Polyelectrolyte Gels in Drug Delivery Date: May 13 Time: Noon to 1 Place: BSBE 6-101 Ron Siegel of Pharmacology will present: "Polyelectrolyte Gels in Drug Delivery" Abstract: Polyelectrolyte gels are capable of undergoing first order phase transitions in response to changes in ambient temperature, pH, ionic environment, temperature, light, and concentration of specific ligands.We are researching methods to harness these transitions in order tomodulate rates of delivery of drugs, particularly hormones. After a brief review of gel physical chemistry, I will discuss two specific delivery systems:1) a gel-gated microfluidic system that delivers insulin in reponse tochanges in ambient glucose level; and 2) a gel/enzyme system that pulsates in swelling, and releases gonadotropin releasing hormone in rhythmicpulses, where the mechanism stems from a dissipative, chemomechanical feedback instability.