Synthesis and characterization of biodegradable non-toxic poly(ester-urethane-urea)s based on poly(ε-caprolactone) and amino acid derivatives

Segmented poly(esterurethane urea)s from novel urea–diol chain extenders: Synthesis, characterization and in vitro biological properties

“…The analysis confirmed that oligomers were constituted by TEG + CL units, and the ratio of CL to TEG signals afforded the value of Mn. Following the same analysis previously reported [5], the PCL spectrum revealed the presence of two different types of TEG units: monosubstituted TEG species (HO-TEG-PCL-OH, 9.58%) and disubstituted TEG species (HO-PCL-TEG-PCL-OH, 90.42%). No free TEG species were found.…”

“…For this reason, great care was taken to determine the molecular weight of the macrodiol as accurately as possible before starting the synthesis of the polyurethanes [5]. 1 H NMR afforded structural information on PCL diol.…”

“…The development of biodegradable and biocompatible SPU and polyurethane networks with labile moieties susceptible to hydrolysis in the polymer backbone has been a subject of considerable interest in recent years [2][3][4][5]. The highly variable chemistry of SPU may be used to generate polymers that exhibit a wide range of physical and chemical properties.…”

“…There are several examples of chain extenders reported in the literature, including (i) short-chain diamines: 1,4-butanediamine or putrescine (BDA) [11][12][13][14], and amino acids or amino acid derivatives such as L-lysine ethyl ester or L-ornithine ethyl ester [5,15] and L-phenylalanine-based diester [16,17]; (ii) short-chain diols: 1,4-butanediol (BDO) [14,18,19], 1,4:3,6-dianhydro D-sorbitol or isosorbide diol [20], cyclohexane dimethanol [21], ethambutol dihydrochloride [22], 1,3-propanediol [23], 3-hexine-2,5-diol [2], and triblocks of BDO-BDI-BDO [14,24]; (iii) short-chain amino-diols such as 2-amino-1-butanol [20]; (iv) sulphydryl compounds such as 2-mercaptoethyl ether [20]; and (v) short-chain diurea-diphenols based on tyramine or tyrosine [10,25]. Water was also used to create hard segments of different lengths through urea-linkage formation [26].…”

Optimization of the structure of polyurethanes for bone tissue engineering applications

“…For example, a positive effect of carbonyl groups has been demonstrated [45][46][47]. Carbonyl groups in the obtained PUR chains resulted from ester bonds in the PCL soft segments and from carbonyls in the urethane groups.…”