Synthetic biodegradable polymers have seen a dramatic increase in their availability and utilization over the last few decades. The first reported biomedical application of biodegradable polymers was during the 70s in biodegradable sutures and to date, it remains as the most widespread usage of this family of materials. Biodegradable polymers have also been proven to be effective carriers in local drug delivery therapies and are widely used as a primary constituent of scaffolds in tissue engineering applications. The usage of biodegradable polymers in the medical field can be dichotomized in two different trends. When used for prosthetic purposes in orthopaedics, the contribution of the polymer is required for a finite period of time, the healing time, and the material can be tailored to degrade at a rate that will transfer the load to the healing bone. On the other hand, for drug delivery implants, attention is shifted to delivery kinetics and its changes during degradation. An emerging application for biodegradable polymers is its employment in endovascular drug eluting biodegradable stents. This kind of application is a bridge connecting the two distinct approaches: the stent must perform mechanically, maintaining the artery patent after deployment and during degradation and must be capable of effective drug delivery. Polymer degradation is the chain scission process that breaks polymer chains down to oligomers and finally monomers. Extensive degradation leads to erosion, which is the process of material loss from the polymer bulk. Polymers degrade by several different mechanisms, depending on their inherent chemical structure and the environmental conditions to which they are exposed. The prevailing mechanism of biological degradation of synthetic aliphatic polyesters (the main class of biodegradable polymers used in biomedical applications) is scission of the hydrolytically unstable backbone chain by passive hydrolysis.
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