Bioresorbable polymers production process

In this chapter, the main aspects related to production process, regulatory approval, and commercialization of a bioresorbable polymer—based medical device are discussed, and several notable examples of commercial products are presented. 

When designing a medical device based on a bioresorbable polymer, the degradation ability of the material during all the phases from the synthesis to the complete resorption in vivo must be carefully considered. In this regard, synthetic polymers are more versatile compared to natural origin polymers, thereby allowing a finer control of the theoretical degradation rate. However, this rate depends from a number of external factors such as production process conditions (eg, humidity, temperature) and site of implantation (eg, pH, mechanical stress) [13—18]. 

The choice of the right suppliers for raw materials is critical because validation of a bioresorbable polymer includes the characteristics of all the suppliers involved in the production process, ie, their quality systems and certifications. An unreliable supplier represents a possible source of issues when producing a device under regulatory approval. For example, a supplier could fail obliging the company to begin a validation process for the new supplier, the quality of the raw material could be erratic, or the supply of a determined material could be discontinued [20]. Moreover, in the past years the number of suppliers of bioresorbable materials did not increase as expected,... 

Processing and production of bioresorbable polymer scaffolds for tissue engineering... 

Synthetic bioresorbable polymers offer several advantages over namral polymers in the development of TE scaffolds (1) they can be produced on a large scale, at low cost, and in a reproducible manner (2) they have no risk of immunogenicity (3) they are easier to process and (4) their properties and degradation kinetics can be easily tailored for the required application. Main drawbacks are that they are less biocompatible than natural polymers and they typically do not present cell recognition sites. In addition, the degradation products of many of them are not natural metabolites and might cause problems if accumulated. 

MW and MW distribution are important factors in polymer degradation because of the autocatalytic character of aliphatic polyester hydrolysis. Vert et al. recommended the elimination of low MW products by the dissolution-precipitation method [23], a means to minimize degradation on processing. This procedure allowed the same authors to process totally bioresorbable composites composed of a semicrystalline PLA matrix reinforced by PGA fibers [129]. Leeslag et al. also showed that the purification of PLAioo led to a material more resistant to hydrolytic degradation [107]. Pitt et al. found that PLA50 films... 

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