Absorbable sutures copolymer

Copolymers of S-caprolactone and L-lactide are elastomeric when prepared from 25% S-caprolactone and 75% L-lactide, and rigid when prepared from 10% S-caprolactone and 90% L-lactide (47). Blends of poly-DL-lactide and polycaprolactone polymers are another way to achieve unique elastomeric properties. Copolymers of S-caprolactone and glycoHde have been evaluated in fiber form as potential absorbable sutures. Strong, flexible monofilaments have been produced which maintain 11—37% of initial tensile strength after two weeks in vivo (48). 

In general, absorbent sutures are composed of materials that are natural to mammals, such as catgut, and to materials that are either quite susceptible to hydrolysis and/or polymers derived from natural materials such as polyglactin, which is a copolymer of lactic and glycolic acid. Nonabsorbent sutures can be made from natural materials such as cotton, which is a plant material, polymers that range from being hydrophobic to hydrophilic, and steel. 

Most of the studies on PLA degradation have concentrated on abiotic hydrolysis [35-37]. The effects of, e.g., residual monomer and other impurities, molecular weight and copolymerization on hydrolysis rate and properties have been studied [3,37-42]. Impurities, residual monomer [43,44], and peroxide modification [45] all increase the hydrolysis rate, while copolymerization can either increase (GA-copolymers) or decrease (CL, DXO-copolymers) the hydrolysis rate. Degradation of PLA and its copolymers in clinical applications ranging from absorbable sutures to drug delivery systems and artificial ligaments has also been widely studied [46-48]. 

PGA has been known as a polymer capable of forming tough fibres however, due to its hydrolytic instability its use has initially been limited. Currently, PGA and its copolymers with either lactic acid or with e-caprolactone are widely used as a material for the fabrication of absorbable sutures. 

The polyester named Lactomer is an alternating copolymer of lactic acid and glycolic acid. Lactomer is used for absorbable suture material because stitches of Lactomer hydrolyze slowly over a two-week period and do not have to be removed. The hydrolysis products, lactic acid and glycolic acid, are normal metabolites and do not provoke an inflammatory response. Draw the stmeture of the Lactomer polymer. 

Absorbable sutures are collagen sutures, polyglycolic acid and its lactide copolymers, and polydioxanone. Nonabsorbable sutures include silk, cotton, polyethylene, polypropylene, nylon, PET, and stainless steel. These fibers can be used as monofilaments or multifilaments (twisted or braided). Figure 2.16 shows examples of filters for medical purposes made of polyester, nylon, and metallic fibers. In summary, fibers are used in almost everything that we can see in our... 

Chu CC. The effect of pH on the in vitro degradation of poly (glycolide lactide) copolymer absorbable sutures. / Biomed Mater Res 1982 16 117-124. 

The first synthetic absorbable suture was made from a homopolymer of glycolic acid by Davis Geek Co. and manufactured with the tradename Dexon (1970). This suture was followed by a second material produced by Ethicon, Inc., in 1974, a copolymer of lactide and glycolide known as poly-glactine 910 or Vicryl. Both Vicryl and Dexon are made from polymer fibers, which are braided to produce sutures. In addition. Vicryl is Teflon coated for... 

The multifilament, coreless suture is preferably made of an absorbable material, such as a segmented lactide copolymer (such as those described in Chapter 2 of this book). The first sealing member 1, second sealing member 3, and the elongated member 2 are made of the flexible absorbable polyaxial copolymer, such as those described in Chapter 3. 

Owing to its hydrolytic instability, initially, its use was limited. Currently, polyglycolide and its copolymers poly(lactic-co-glycolic acid) with lactic acid, poly(glycolide-co-caprolactone) with e-caprolactone, and poly(glycolide-co-trimethylene carbonate) with trimethylene carbonate) are widely used to develop synthetic absorbable sutures that were marketed under the trade name of Dexon and are now sold as Surgicryl [61],... 

When 1,4-butanediol is supplied in different amormts as a carbon source, P(3HB-co-4HB) is biosynthesized with 4HB contents of 5-40mol.%. This copolymer has excellent elongation to break and thermal properties for various applications. Metabolix, USA, and Tianjin Green Bioscience, China, together with DSM, The Netherlands, announced plans to produce 50 000 and 10 000 tons per year, respectively.On the other hand, Tepha, USA, produces P(4HB) (TephaFLEX) for medical applications as absorbable sutures and srugical meshes. 

Polymers in the group of polyesters, specifically the family of polyflactic acid) (PLA), polyfglycolic acid) (PGA), and copolymers of lactic and glycolic acids (PLGAs), as well as poly(P-hydroxybutyric acid) (PHB) most closely fulfilled the criteria outlined above, including biocompatibility, processability, and controlled degradation [8]. These polymers, many descendant of absorbable suture materials developed a couple of decades ago, were approved for in vivo use by the Food... 

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