ABSTRACT
The enzymes or some other biologically active species are involved with degradation. The material itself has to reside within the tissues of the body for as long as its function is required. It should be susceptibility to the type of degradation will vary with the structural characteristic of the polymers, just as it will with other degradation mechanisms. Among the polymers which have been shown to degrade by hydrolysis in vivo are certain polyamides and poly (amino acid) s, some polyurethanes and both aliphatic and aromatic polyesters. If enzymes are able to cause polymer degradation, it might be expected that bacteria could also be involved in this process, especially as much of their activity is mediated by enzymes. In biomedical applications, polyurethanes are described as either poly (ester urethane) s or poly (ether urethane) s. An interesting example of an aliphatic polyester that has been considered in the context of biodegradation is poly (β-hydroxybutyrate) (PHB).
