Poly based absorbable sutures

Poly (L-lactide-co-e-caprolactone)-based absorbable sutures... 

All those commercial synthetic absorbable sutures fabricated from the gly-colide, lactide, e-caprolactone, p-dioxanone, and trimethylene carbonate building blocks can only be degraded via pure hydrolysis. Although it has been suggested that enzymes are involved, the issue is remains unresolved and controversial. There were no truly enzymatically biodegradable synthetic absorbable fibers on the market until the reported studies of amino add-based poly(ester amide)s (AA-PEA). 

Poly(lactic acid) (PLA) (Fig. 1.16) is an aliphatic polyester polymerised by lactic acid which is made by fermentation of natural raw materials, for example, com starch and sugarcanes. Due to the chiral nature of lactic acid and its effects on the polymer s characteristics, the biodegradability and mechanical properties of PLA can be tailored by varying the proportion of different forms. Meanwhile, PLA can also copolymerise with other monomers or blend with other polymers to improve some properties of the material, eg, flexibility. PLA and PLA-based copolymers are the most popular biodegradable materials for the production of absorbable sutures (Li, 1999) (Fig. 1.16). 

A variety of hydrogels have been used in numerous biomedical applications, for example, as material for contact lenses in the field of ophthalmology and as absorbable sutures in surgery, as well as in several new areas of medical practice to cure such disease as osteoporosis, diabetes mellitus, heart diseases, and neoplasms. Professors Lim and Wichterle of Prague, Czech Republic, synthesized the first hydrogel material based on syrrthetic poly-2-hydroxyethyl methacrylate in 1955. The... 

The synthetic absorbable sutures are made from polymers capable of degradation in the biological environment without adverse effects. One overall advantage of absorbable sutures is the elimination of clinical visits for their removal. These sutures are either homopolymers or copolymers based on degradable polymeric units such as polyglycolic acid, polylactic acid, or poly-/ -dioxanone. 

Meanwhile Ethicon (and others) developed alternative absorbable surgical sutures, based, for example, on copolymers of polyglycolide with poly-L-lactide or poly(trimethylene carbonate), and on polydioxanone, and on poly(e-oxycaproate), and also on copolymers of these with polyglycolide or with each other. These different structures made it possible to provide fibres with different rates of absorption, with different degrees of stiffness or flexibility, and for use in monofilaments, braided multifilaments, and other yam structures, as required for different surgical operations. 

Development of completely different biomaterials from the existing commercially available five basic building blocks as sutures has been very rare. Barrows (1986,1994) introduced a new family of synthetic absorbable PEA polymer and fibers in 1990s. He made a series of nonamino acid-based PEAs from poly esterification of diols that contain preformed amide linkages, such as amidediols.The rationale for making PEAs is to combine the well-known... 

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