Some insight into hydrolytic scission mechanisms in bioerodible polyesters

Wiley - Tập 102 Số 4 - Trang 3111-3117 - 2006
Frank Alexis1, Subbu S. Venkatraman2, Santosh Kumar Rath2, Leong‐Huat Gan3
1Institute of Bioengineering and Nanotechnology, Singapore 138669
2School of Materials Engineering,#N#Nanyang Technological University,#N#Singapore 639798
3Natural Sciences, National Institute of Education, Singapore 637616

Tóm tắt

AbstractPLLA, PDLLA, and PLGA copolymers have been studied to understand the details of their degradation behavior. All polymers exhibited a homogeneous mode of degradation, with uniform rates of degradation throughout the film. Crystallinity inhibited water absorption and hence retarded degradation. The degradation rate was increased by the presence of glycolic acid units in the PLGA copolymer; this effect overwhelms any decrease in degradation rate because of increased crystallinity due to the additional GA units. This effect is demonstrated quantitatively in this study. In PLGA polymers, there is evidence of unusual recrystallization behavior as degradation proceeds, due mainly to the higher rate of hydrolytic scission of the glycolide linkage compared with the lactide, as verified quantitatively with the use of 1H NMR studies. Application of a Monte Carlo model to the degradation results, however, appears to show a random scission process. The details of the mechanistic study of different factors influencing the process of degradation, as reported here, may have important implications in terms of selecting the right material for specific biomedical applications. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3111–3117, 2006

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Wiley

Tập 102 Số 4

3111-3117

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