Biodegradability, enzymatic degradation

Very often, parallel to the pure enzymatic degradation, there is also degradation triggered by other influences like chemical hydrolysis, UV light or heat. These influences lead to polymer chain fragmentation, which follows a different mechanism to that of the biodegradation process. In contrast to the pure biodegradation process, these processes affect the bulk of the plastic piece. 

To a large extent, xenobiotic compounds in the aquatic environment are bound with sediments and suspended solid materials, such as humic acids. This binding plays a large role in biodegradation. Indeed, the structure of the bound form of the xenobiotic, such as a humic acid complex with a synthetic organic compound, may largely determine its rate of enzymatic degradation. 

Biodegradable polymers used in the field of controlled drug delivery are typically degraded by hydrolysis [38]. In addition, some biomedical polymers are enzymatically degradable [35,39]. Many factors are known to influence the bio-... 

PIBCA nanospheres were injected subcutaneously to rats. Autoradiographic pictures obtained after using radiolabelled polymer have shown a progressive staining reduction in the muscular tissue suggesting that nanospheres were slowly biodegraded. In the same study, nanospheres were found to release a peptide (GRF) in a sustained manner. Comparison of the AUC of free GRF and GRF-loaded nanospheres showed that in addition to the slow release process nanospheres were able to improve the bioavailability of the peptide. This improvement could be attributed to the fact that free administered GRF is very quickly metabolized at the injection site, whereas it is partly protected from massive enzymatic degradation when it is administered associated with nanospheres. ... 

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