Polylactide medical applications

At the time of writing, the applications of biodegradable polymers are confined mostly to the field of agriculture, where they are used in products with limited lifetimes, such as mulch films and pellets for the controlled release of herbicides. The synthetic polyesters used in medical applications, principally polylactide and poly(lactide-co-glycolide), while claimed to be biodegradable, are degraded in the body mainly, if not entirely, by chemical hydrolysis. There is little evidence that the hydrolysis of these polyesters of a-hydroxyacids can be catalyzed by hydrolase or depolymerase enzymes. 

Kricheldorf, H.R. and Kreiser-Sauders, I. (1996) Polylactides-synthesis, characterization and medical application. Macromolecular Symposia, 103, 85-102. 

Kricheldorf, H. R. Kreiser-Saunders, I. Polylactides—synthesis, characterization and medical application. Macromol. Symp. 1996,103, 85-102. 

Figure 2.1 Basic structures for some groups of synthetic polymers commonly employed as degradable materials in medical applications a) polylactide-co-polyglycolides (also commonly used as their homopolymers (i.e., n/m = 0), b) polycaprolactones, c) polydioxanones, d) polyorthoesters, e) polyanhydrides, f) polyalkylcyanoacrylates, g) poly(organo)phosphazenes and h) polyphosphoesters...

Bendix, D., 1998. Chemical synthesis of polylactide and its copolymers for medical applications. Pol5Tn. Degrad. Stabil. 59, 129—135. 

There are important medical applications for polylactides prepared from the lactide dimer as well as for lactide-glycolide copolymers synthesized from lactide and glycolide dimers. These polymers are used for procedures requiring surgical sutures, implants, bone plates, and controlled drug release, inasmuch as they are biocompatible, biodegradable, and resorbable materials. 

In the case of polylactides and PCL, the synthesis by dispersion polymerization does not provide any advantage over polymerizations in bulk. However, for preparation of materials for various medical applications, when biodegradable particles with the narrow diameter dispersity, composed of polymers with the narrow molecular weight distribution, are needed, the dispersion polymerization may be the choice. 

H. Tsuji, Polylactides, Biopolymers for Medical and Pharmaceutical Applications, Wiley-VCH, USA, 2005, pp. 183-219. 

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