Poly Ester Amides PEAs

Key words collagen, poly-p-dioxanone (PDS), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), polybutester, polyamide, polytetrafluoroethylene (PTFE), stainless steel, poly(ester amide) (PEA), amino acid poly(ester amide) (AA-PEA). 

With regards to new polymeric biomaterial, Gomurashvilli and co-workers (2) have developed new biodegradable and tissue-resorbable co-poly(ester amides) (PEAs) using a versatile Active PolyCondensation (APC) method which involves di-p-toluenesulfonic acid salts of bis-(L-a-amino acid)-a,(o-alkylene diesters and active diesters of dicarboxylic acids as monomers. A wide range of... 

Poly(ester amides) (PEAs) are a class of synthetic polymers bearing both ester and amide repeat units (Scheme 2.9). These repeat units along the polymer chain can be... 

Poly (ester amides) (PEA) poly(ortho ester amide) (POEA) copolymers... 

Property Poly(capro lactone) (PCD Poly(ester amide) (PEA) Poly(butylene succinate/adipate) (PBSA) Polyfbutylene adipate-co-terephthalate) (PBSA) Poly( vinyl alcohol) (PVA)... 

The segmented polyamide elastomers are synthesized from MDI (4,4 -diisocyanato-diphenylmethane) and dicarboxylic acids and a carboxylic acid terminated aliphatic polyester, polycarbonate or polyether prepolymer with an average molecular weight of M = 500-5000. The dicarboxylic acids used as hard segment extenders are adipic and azelaic acid. Also, poly(ester amide) alloys are obtained using nylon-6,6 or polyesters (PEA/PBT). 

J.D. Sudha, C.K.S. Pillai, Synthesis and properties of amphotropic hydrogen bonded Uquid crystalline (LC) poly(ester amide)s (PEA) effect of aromatic moieties on LC behavior. Polymer 46 (2005) 6986-6997. 

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). 

SEM image of phenylalanine-based poly(ester amide) fibre in PBS buffer medium, 314 in vitro enzyme hydrolysis of L-Phenylalanine-based PEA fibres, 313... 

M-PEG-NH2 = Methoxy-PECTAmine NCA = N-carboxy anhydride NMP = N-methyl-2-pyrrolidone NMR = Nuclear Magnetic Resonance PEA = Poly(ester-amides)... 

Cycloaliphatic LC PEAs based on commercially poly(l,4-cyclohexanedimelhylene terephthalate) (PCX) have also been synthesized with two cycloaliphatic diamines and a linear counterpart (1,6-hexamethylenediamine) (Figure 8.12) [55]. The compositions of the ester/amide units in the copolymers were varied up to 50% by the adjustment of the amounts of the diol and diamine in the feed. The introduction of amide linkages was found to induce nematic LC properties into the polyester backbone, which in turn increased the polymer chain alignment. Interestingly, the introduction of nematic LC phases into PCT was only possible when a low ratio of amide units (i.e., less than 25 mol%) was incorporated into the polymer backbone. 

The first dendrimers made were based on PAMAM (Tomalia et al. 1985). It was also the first to be scaled up and commercialized under the name of starburst dendrimers. Poly(propylene imine) (PPI) and poly(ethylene imine) (PEI) are some of the other commonly used dendrimers for drug and gene delivery. Since then, many new dendrimers have been synthesized that possess various properties for specific applications. Incorporation of inorganic molecules into dendrimer structures has shown distinct advantages. For example, the recent carbosilane dendrimers with surface lactose entities seem to possess inherent antiviral properties (Oka et al. 2009). In another case, fluorine molecules were incorporated into the core of dendrimers (Jiang and Yu 2010) that offer potential in fields such as catalysis. Polyester (Padilla De Jesus et al. 2002), polypeptide (Choe et al. 2002), triazine (Lim and Simanek 2008), and poly glycerol (Calderon et al. 2009) are organic dendrimers that have been attached to chemothera-peutics to increase the efficacy of treatment. Many other useful chemical compositions such as the poly (ester acrylate/amide) (PEA) (Swanson et al. 2007) and poly(ether hydroxylamine) (PEHAM) (Tomalia et al. 2006) are commercially available and used in biomedical applications. 

Esters obtained from the degradation of poly(ethylene terephthalate) (PET) can be used as raw materials for PPA [24]. PEA can be condensed after the degradation of the polyester used. The ester groups can be converted almost completely into amide groups. After removal of the alcohols and diols released, the materials can be processed in a conventional manner. 

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