Symmetrical biodegradable crosslinkers for use in polymeric devices
摘要:
There is a need for biodegradable hydrogels that deteriorate at defined rates under physiological conditions for use in engineered tissue constructs and drug delivery. These hydrogels should contain components that are readily synthesized, biocompatible and easily incorporated into hydrogel networks. This need was addressed through a judiciously designed series of crosslinkers composed of symmetrical oligo-glycolate and oligo-lactate esters terminated with vinylic moieties (1). These materials were incorporated into poly(HPMA) networks via free-radical polymerization. This work describes the preparation of symmetrical, lactate and glycolate ester based crosslinking agents and their incorporation into a hydrogel network composed of 2-hydroxypropyl methacrylamide (HPMA). By varying the number of lactic and glycolic acid residues (n = 0, 1, 2) within the crosslinker, the rate of hydrolytic degradation of the gel can be controlled. (c) 2005 Elsevier Ltd. All rights reserved.
Symmetrical biodegradable crosslinkers for use in polymeric devices
作者:Allen A. Thomas、In Tae Kim、Patrick F. Kiser
DOI:10.1016/j.tetlet.2005.10.066
日期:2005.12
There is a need for biodegradable hydrogels that deteriorate at defined rates under physiological conditions for use in engineered tissue constructs and drug delivery. These hydrogels should contain components that are readily synthesized, biocompatible and easily incorporated into hydrogel networks. This need was addressed through a judiciously designed series of crosslinkers composed of symmetrical oligo-glycolate and oligo-lactate esters terminated with vinylic moieties (1). These materials were incorporated into poly(HPMA) networks via free-radical polymerization. This work describes the preparation of symmetrical, lactate and glycolate ester based crosslinking agents and their incorporation into a hydrogel network composed of 2-hydroxypropyl methacrylamide (HPMA). By varying the number of lactic and glycolic acid residues (n = 0, 1, 2) within the crosslinker, the rate of hydrolytic degradation of the gel can be controlled. (c) 2005 Elsevier Ltd. All rights reserved.
Oligo-α-hydroxy Ester Cross-Linkers: Impact of Cross-Linker Structure on Biodegradable Hydrogel Networks
作者:Kenneth D. Eichenbaum、Allen A. Thomas、Gary M. Eichenbaum、Brian R. Gibney、David Needham、Patrick F. Kiser
DOI:10.1021/ma0518306
日期:2005.12.1
We describe the synthesis of a series of biodegradable oligo-alpha-hydroxy ester cross-linkers and evaluate their impact on the degradation kinetics and macromolecule diffusion from a hydrogel network. By changing the steric and electronic environment at the site of degradation in the cross-linker, we were able to modulate the degradation, swelling kinetics, and corresponding release profiles of macromolecules from poly(HPMA) hydrogel networks under physiologically relevant conditions. As the steric hindrance and electron demand at the site of hydrolysis for three different cross-linkers was increased, the total time for the hydrogel network to completely dissolve increased from 2 to over 30 days while incubated in pH 7 buffer. As the number of hydrolyzable sites and the electron demand at the side of hydrolysis decreased, the time to completely dissolve decreased from weeks to several days. Increasing the cross-linking density for one of the degradable cross-linkers (1.5% to 3.0% feed ratio) increased the degradation time by several weeks. Burst release was absent for high molecular weight solutes because the release rate depended on controlled degradation of the polymer network and an increase in average network mesh size. The synthetically adaptable cross-linkers described herein offer a new approach for controlling the rate and extent of release from biodegradable hydrogel networks.