New associative systems based on alkylated hyaluronic acid. Synthesis and aqueous solution properties

Periodate Oxidation of Methylcellulose: Characterization and Properties of Oxidized Derivatives

“…Methylcellulose Methocel A15 Premium LV is produced by Dow Chemical (Mv~31500; DS~1.8); this sample was used for the study of oxidation by metaperiodate. HA-ADH was a gift from ARD company (Pomacle, France) and was prepared following a previously described method [13,14].The synthesis was performed in presence of EDC at ambient temperature and pH = 4.75; after reaction, the product is purified by diafiltration in dilute solution (1 g/L) and used directly; the initial weight-average molecular weight of HA is 300,000 g/mol.…”

“…After addition of the reducing agent (here NaBH 3 CN), pH was stabilized at a value around 6 and left under stirring during 24 hours before isolation and purification. To prepare 3D-networks, oxidized methylcelluloses were added in their solid form in a solution of chitosan or hyaluronan-ADH [11,13,14]. After complete dissolution, the reductive agent was added and the method used was the same as described for simple amine.…”

“…We want to add complementary data upon application of this reaction on chitosan and on hyaluronan-ADH; this ADH derivative permits control of the −NH 2 yield along the HA backbone; usually it is around 8% of groups per disaccharide repeat unit in our work [13,14].…”

Self-assembly and emulsification of dopamine-modified hyaluronan

“…S2, which was used to calculate the CAC values of HA-DOPA as described elsewhere (Wang et al, 2005). The CAC values of HA-DOPA (listed in Table 1) were much lower than other hydrophobic-modified polysaccharides such as alkylated derivatives of HA (0.5 mg/mL) (Creuzet, Kadi, Rinaudo, & Auzely-Velty, 2006) and N-alkyl modified sulfated chitosan (0.45 mg/mL) (Zhang, Qineng, & Zhang, 2004), indicating that HA-DOPA have a strong tendency to form nanoparticles through hydrophobic interactions between the DOPA segments. Furthermore, HA-DOPA with higher DOPA contents exhibited lower CAC value, which show clearly that the increase of DOPA segment facilitated the self-assembly of HA-DOPA.…”

Metastable Amphiphilic Hydrogels Based on Crosslinked Carboxymethylpullulan

“…27 The effect of temperature on hydrophobic associations has been discussed by some authors who worked on hydrophobically modified polymers. But they do not agree: most of them think that the temperature strengthens the hydrophobic interactions, 28,29 while others claim that it is the opposite. Considering our results, our systems act more like the latter, with hydrophobic associations which reorganize as a function of time and temperature.…”