Molecular characteristics and antioxidant activity of polyethylene glycols modified by sterically hindered phenols

Abstract

Chemical modification of polyethylene glycols by antioxidants belonging to the class of sterically hindered phenols is used to obtain water-soluble conjugates differing in the structure of the joined antioxidant and molecular weight. The inclusion of hydrophobic end groups in polyethylene glycol molecules leads to a decrease in the lower critical mixing point of the solution as compared to the original polymer. Dilute solution viscometry and light scattering are used to determine the molecular-mass characteristics of the polymers and the hydrodynamic radii of single conjugate molecules. The mass fraction of single molecules in aqueous solutions of the conjugates is greater than 95%. The aggregates are micellar-type particles whose core is formed by the hydrophobic moieties of sterically hindered phenols. It is shown that the antiradical activity of the antioxidants 3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propionic acid and 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid, which are used for the modification, differs only slightly, whereas the activity of the relevant conjugates increases significantly.

Engineering biodegradable polyester elastomers with antioxidant properties to attenuate oxidative stress in tissues

“…Previous attempts to limit biomaterial-induced oxidative stress included synthesizing polymers that lead to charge-neutral degradation products [18], which does not inhibit oxidative stress induced by other factors, and conjugating antioxidant molecules to the surface of the biomaterial to provide local antioxidant therapy [19–21]. Examples of the latter include the conjugation of small molecule antioxidants such as superoxide dismutase mimetics (mSOD), vitamin E, gallic acid, catechin, ascorbic acid and glutathione to ultra-high molecular weight poly(ethylene) (UHMPE), poly(acrylic acid), gelatin, poly(methyl methacrylate) and poly(ethylene glycol) [22–26].…”

Stem cells, growth factors and scaffolds in craniofacial regenerative medicine

“… 107 , 108 , 109 , 110 , 111 Approaches to minimizing the inflammatory response include incorporation of biomimicking materials as well as conjugate antioxidants in the scaffold itself. 112 , 113 , 114 , 115 Utilizing scaffolds that can be delivered through minimally invasive techniques, such as injectable hydrogels or thermoresponsive scaffolds, is also an important tactic to reduce inflammation. 116 , 117 …”

Future and the past of polymeric antioxidants

“…To create HMAO, we used the method of chemical modification of hydrophilic polymers with various antioxidants, making possible a targeted design of the macromolecular systems with antioxidant properties 62‐80,83‐89,99‐101 …”

“…Already at the design stage of macromolecular systems, their possible application area was predefined 63‐65,68‐78,85,86 . For instance, HMAOs prepared from polysaccharides (dextran, hydroxyethyl starch) that can serve as blood plasma expanders, could be used for the same purpose, in case they remain water soluble after the modification with hydrophobic antioxidants 63,68 …”

“…The choice of polyethylene glycols (PEG) derivatives devised new opportunities for varying HMAOs properties and applications. PEG is a well‐known polymer in medicine and pharmaceutics due to its unique solubility in both aqueous and organic media 74,75 …”