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Hyaluronic Acid-Poly(N-acryloyl glycinamide) Copolymers as Sources of Degradable Thermoresponsive Hydrogels for Therapy

One-pot free-radical polymerization of N-acryloyl glycinamide in the presence of hyaluronic acid as transfer-termination agent led to new copolymers in high yields without any chemical activation of hyaluronic acid before. All the copolymers formed thermoresponsive hydrogels of the Upper Critical So...

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Autores principales: Boustta, Mahfoud, Vert, Michel
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7709696/
https://www.ncbi.nlm.nih.gov/pubmed/33238369
http://dx.doi.org/10.3390/gels6040042
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author Boustta, Mahfoud
Vert, Michel
author_facet Boustta, Mahfoud
Vert, Michel
author_sort Boustta, Mahfoud
collection PubMed
description One-pot free-radical polymerization of N-acryloyl glycinamide in the presence of hyaluronic acid as transfer-termination agent led to new copolymers in high yields without any chemical activation of hyaluronic acid before. All the copolymers formed thermoresponsive hydrogels of the Upper Critical Solution Temperature-type in aqueous media. Gel properties and the temperature of the reversible gel ↔ sol transition depended on feed composition and copolymer concentration. Comparison with mixtures of hyaluronic acid-poly(N-acryloyl glycinamide) failed in showing the expected formation of graft copolymers conclusively because poly(N-acryloyl glycinamide) homopolymers are also thermoresponsive. Grafting and formation of comb-like copolymers were proved after degradation of inter-graft hyaluronic acid segments by hyaluronidase. Enzymatic degradation yielded poly(N-acryloyl glycinamide) with sugar residues end groups as shown by NMR. In agreement with the radical transfer mechanism, the molar mass of these released poly(N-acryloyl glycinamide) grafts depended on the feed composition. The higher the proportion of hyaluronic acid in the feed, the lower the molar mass of poly(N-acryloyl glycinamide) grafts was. Whether molar mass can be made low enough to allow kidney filtration remains to be proved in vivo. Last but not least, Prednisolone was used as model drug to show the ability of the new enzymatically degradable hydrogels to sustain progressive delivery for rather long periods of time in vitro.
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spelling pubmed-77096962020-12-03 Hyaluronic Acid-Poly(N-acryloyl glycinamide) Copolymers as Sources of Degradable Thermoresponsive Hydrogels for Therapy Boustta, Mahfoud Vert, Michel Gels Article One-pot free-radical polymerization of N-acryloyl glycinamide in the presence of hyaluronic acid as transfer-termination agent led to new copolymers in high yields without any chemical activation of hyaluronic acid before. All the copolymers formed thermoresponsive hydrogels of the Upper Critical Solution Temperature-type in aqueous media. Gel properties and the temperature of the reversible gel ↔ sol transition depended on feed composition and copolymer concentration. Comparison with mixtures of hyaluronic acid-poly(N-acryloyl glycinamide) failed in showing the expected formation of graft copolymers conclusively because poly(N-acryloyl glycinamide) homopolymers are also thermoresponsive. Grafting and formation of comb-like copolymers were proved after degradation of inter-graft hyaluronic acid segments by hyaluronidase. Enzymatic degradation yielded poly(N-acryloyl glycinamide) with sugar residues end groups as shown by NMR. In agreement with the radical transfer mechanism, the molar mass of these released poly(N-acryloyl glycinamide) grafts depended on the feed composition. The higher the proportion of hyaluronic acid in the feed, the lower the molar mass of poly(N-acryloyl glycinamide) grafts was. Whether molar mass can be made low enough to allow kidney filtration remains to be proved in vivo. Last but not least, Prednisolone was used as model drug to show the ability of the new enzymatically degradable hydrogels to sustain progressive delivery for rather long periods of time in vitro. MDPI 2020-11-23 /pmc/articles/PMC7709696/ /pubmed/33238369 http://dx.doi.org/10.3390/gels6040042 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Boustta, Mahfoud
Vert, Michel
Hyaluronic Acid-Poly(N-acryloyl glycinamide) Copolymers as Sources of Degradable Thermoresponsive Hydrogels for Therapy
title Hyaluronic Acid-Poly(N-acryloyl glycinamide) Copolymers as Sources of Degradable Thermoresponsive Hydrogels for Therapy
title_full Hyaluronic Acid-Poly(N-acryloyl glycinamide) Copolymers as Sources of Degradable Thermoresponsive Hydrogels for Therapy
title_fullStr Hyaluronic Acid-Poly(N-acryloyl glycinamide) Copolymers as Sources of Degradable Thermoresponsive Hydrogels for Therapy
title_full_unstemmed Hyaluronic Acid-Poly(N-acryloyl glycinamide) Copolymers as Sources of Degradable Thermoresponsive Hydrogels for Therapy
title_short Hyaluronic Acid-Poly(N-acryloyl glycinamide) Copolymers as Sources of Degradable Thermoresponsive Hydrogels for Therapy
title_sort hyaluronic acid-poly(n-acryloyl glycinamide) copolymers as sources of degradable thermoresponsive hydrogels for therapy
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7709696/
https://www.ncbi.nlm.nih.gov/pubmed/33238369
http://dx.doi.org/10.3390/gels6040042
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