Ultrasound-enhanced polymer degradation and release of incorporated substances.

J. Kost, K. Leong, R. Langer

Research output: Contribution to journalArticlepeer-review

284 Scopus citations

Abstract

The effect of ultrasound on the degradation of polymers and the release rate of incorporated molecules within those polymers was examined. Up to 5-fold reversible increases in degradation rate and up to 20-fold reversible increases in release rate of incorporated molecules were observed with biodegradable polyanhydrides, polyglycolides, and polylactides. Up to 10-fold reversible increases in release rate of incorporated molecules within nonerodible ethylene/vinyl acetate copolymer were also observed. The release rate increased in proportion to the intensity of ultrasound. Temperature and mixing were relatively unimportant in effecting enhanced polymer degradation, whereas cavitation appeared to play a significant role. Increased release rates were also observed when ultrasound was applied to biodegradable polymers implanted in rats. Histological examination revealed no differences between normal rat skin and rat skin that had been exposed to ultrasonic radiation for 1 hr. With further study, ultrasound may prove useful as a way of externally regulating release rates from polymers in a variety of situations where on-demand release is required.

Original languageEnglish
Pages (from-to)7663-7666
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Volume86
Issue number20
DOIs
StatePublished - 1 Jan 1989

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