Peroxide‐Containing Chitosan Derivative for Hydrogel Synthesis

Abstract

Summary: Peroxide‐containing chitosan was synthesized using a polymer‐analogous reaction between chitosan and tert‐butylperoxymethyl ester of maleic acid. Peroxide‐containing chitosan macromolecules cross‐link into a polymeric hydrogel network in the presence of 1‐vinyl‐2‐pyrrolidone upon heating. Polymeric hydrogels are formed due to reactions of radical chain transfer and recombination. Reacting radical species are chitosan macroradicals and poly(vinylpyrrolidone) macroradicals formed by decomposition of peroxide‐containing fragments. Synthesized hydrogels are pH‐responsive and facilitate drug release.

pH‐Sensitive Chitosan‐based Hydrogel Nanoparticles through Miniemulsion Polymerization Mediated by Peroxide Containing Macromonomer

“…HNp based on Chi and PVP with 3D covalently cross‐linked polymeric network were synthesized by free‐radical graft copolymerization inside the aqueous nanodroplets of inverse miniemulsion. The graft‐copolymerization was initiated by radicals generated from the peroxide‐containing Chi derivative (Chi‐PM) obtained by the polymer analogous reaction . The interaction between primary amine groups in deacetylated Chi fragments and carboxyl groups in PM results in Chi‐PM formation (Scheme ).…”

“…In general, the copolymerization of Chi with the vinyl monomers in presence of radical initiators such as ammonium and potassium persulfate leads to a partial degradation of Chi due to the cleavage of C 1 –C 4 bonds, which makes it difficult to obtain hydrogel network . The advantage of using Chi‐PM is that Chi is not fragmented under the influence of radicals, which are generated by decomposition of peroxide groups of Chi‐PM …”

“…The graft-copolymerization was initiated by radicals generated from the peroxide-containing Chi derivative (Chi-PM) obtained by the polymer analogous reaction. [41] The interaction between primary amine groups in deacetylated Chi fragments and carboxyl groups in PM results in Chi-PM formation (Scheme 1).…”

“…Recently, we have described a promising approach for the synthesis of bulk chitosan‐based hydrogels through radical polymerization of peroxidized chitosan, i.e. chitosan molecules, which are functionalized with peroxide groups through polymer analogues reaction . The advantage of using such a peroxidized chitosan in the formulation of covalently cross‐linked hydrogels is that chitosan molecules are not fragmented under the influence of radicals generated by the decomposition of peroxide groups, thus the efficiency of cross‐linking can be controlled.…”

“…chitosan molecules, which are functionalized with peroxide groups through polymer analogues reaction. [41] The advantage of using such a peroxidized chitosan in the formulation of covalently cross-linked hydrogels is that chitosan molecules are not fragmented under the influence of radicals generated by the decomposition of peroxide groups, thus the efficiency of cross-linking can be controlled. In the current work, the novelty lies in the following: (i) formulation of chitosan-based hydrogel particles in a nanometer size range through graft-copolymerization of 1-vinyl-2-pyrrolidone (VP) and peroxidized chitosan inside the miniemulsion droplets, and (ii) evaluation of the pHsensitivity and swelling behavior of the obtained hydrogel nanoparticles using two different fluorescent dyes rhodamine 123 and sulforhodamine 101 (as model drugs), which are of cationic and anionic nature, respectively.…”