Development of acidity in non-ionic surfactants: formic and acetic acid

A Quantitative Kinetic Study of Polysorbate Autoxidation: The Role of Unsaturated Fatty Acid Ester Substituents

“…This upper limit is an order of magnitude lower than the measured PS-20 oxidizability and indicates the unsaturated fatty acids present in the PS-20 sample used here could not account for the measured oxidizability constant. This supports the contention that the autoxidation of the polyethylene glycol groups is the major contribution to the oxidation of PS-20, consistent with the studies by Donbrow on PS-20 and other non-ionic surfactants (12,23). A more detailed study of the classical kinetics of PS-20 oxidation is being executed to study the contribution of ethylene oxide substituents.…”

“…(2). The results were considered to be consistent with Donbrow's polyoxyethylene chain autoxidation mechanism (12,23,24).…”

“…The oxidation mechanism of polysorbates was first described by Donbrow et al based on their seminal work with PS-20 (12,23,24). PS-20 oxidation was studied by monitoring the formation of peroxides, changes in acidity, and the generation of organic acids and other products.…”

The Degradation of Polysorbates 20 and 80 and its Potential Impact on the Stability of Biotherapeutics

“…Polysorbates are known to be degraded by autooxidation and hydrolysis (16,(18)(19)(20)(21). This could lead to a decrease in the apparent concentration of polysorbate in the protein formulation over long shelf life, the rate of decrease being proportional to increasing temperature.…”

Identification of a Yellow Impurity in Aged Samples of Aqueous Butamben Suspension: Evidence for the Oxidative Degradation of Poly(ethylene glycol)

“…There is precedent in the literature for oxidative degradation of PEG and for carbonyl-containing degradants causing the decomposition of oxidizable drugs. [14][15][16][17][18] The fact that samples that are purged with nitrogen (<2% oxygen) at the time of filling do not turn yellow after several years lends support to the proposed oxidative mechanism.…”