On the mechanism of scission of alginate chains by periodate

Periodate oxidation of sodium alginate in water and in ethanol–water mixture: a comparative study

“…The free radical-independent degradation has been attributed to the cleavage of infrequent and unusual monomers in the alginate resulting in the breakage of the main chains. 12 Free radical-mediated polymer cleavage is due to the generation of radicals during oxidation of phenolic impurities present in alginate and aliphatic alcohols such as propanol have been shown to inhibit this cleavage by acting as a freeradical scavenger. 9,12,13 We believe the extensive polymer cleavage seen in ethanol-water mixture is due to the generation of more reactive hydroxyethyl radicals during oxidation 14 (as opposed to the more stable and less reactive hydroxypropyl radicals when propanol was incorporated in the reaction medium) along with hydroxide radicals cleaving the glycosidic bonds in alginate.…”

“…12 Free radical-mediated polymer cleavage is due to the generation of radicals during oxidation of phenolic impurities present in alginate and aliphatic alcohols such as propanol have been shown to inhibit this cleavage by acting as a freeradical scavenger. 9,12,13 We believe the extensive polymer cleavage seen in ethanol-water mixture is due to the generation of more reactive hydroxyethyl radicals during oxidation 14 (as opposed to the more stable and less reactive hydroxypropyl radicals when propanol was incorporated in the reaction medium) along with hydroxide radicals cleaving the glycosidic bonds in alginate. It is seen that although there is drastic reduction in the M w from the parent value in this medium, this reduction is not reflected with respect to increasing periodate concentrations except for very high periodate equivalent.…”

Novel alginate–acrylic polymers as a platform for drug delivery

“…Note that, with the DOSY map, it is also possible to evidence the presence of low molecular weight compounds showing a fast value of the diffusion coefficient. This is not unexpected, as peroxides may cause a degradation of AA as side reaction, 29 and the formation of oligomers during the radical polymerization of acrylics is also well known.…”

Biodegradable IPNs based on oxidized alginate and dextran-HEMA for controlled release of proteins

“…Periodate is able to split the vicinal diols in alginate, forming the corresponding dialdehyde derivative ( Fig. 1) (Scott et al, 1976). The ratio of sodium periodate to the num- Fig.…”

“…It has been shown that oxidation of alginate with periodate leads to cleavage of the C2-C3 bond in the monosaccharide units thus forming a dialdehyde derivative. This derivative is susceptible to alkaline ␤-elimination (Scott, Tigwell, Phelps, & Nieduszynski, 1976;Veelaert, de Wit, Gotlieb, & Verhé, 1997), leading to a decrease of the polymer molecular weight.…”