Chitosan-Graft-Polyacrylamide Based Release Systems: Effect of pH and Crosslinking

Abstract

This study covers the synthesis and release behavior of chitosan-graft-polyacrylamide copolymers in aqueous media at different pH values. The copolymers were synthesized using redox polymerization with ceric ammonium nitrate (CAN) in 1% aqueous acetic acid solution as the initiator. Optimum condition for the graft copolymer synthesis was determined as 3.85 g/L chitosan, 0.27 M acrylamide (AAm) monomer at 40 °C with a CAN per gram chitosan as 6 mmol using 0.05 M stock solution in 0.1 N HNO3. Then the crosslinked copolymers were synthesized using methylenebisacrylamide (MBA) as a crosslinker varying mass proportions of AAm:MBA as 15:1, 20:1, and 30:1. Obtained material amount (polymer yield) and molecular weight of crosslinked copolymers were lower than the graft copolymer as expected. Acetylsalicylic acid (ASA) release behaviors of all copolymers were monitored with UV-visible spectroscopy at different pH values (2, 6, and 8.5) corresponding to different media in the body (stomach, skin, and intestine, respectively). According to the results, the release behavior changed the least among the samples with respect to medium pH and of was the most affected.

Keywords

• Drug Delivery Systems
• Chitosan
• Emulsion Polymerization
• Graft Copolymers

References

1. 1. Shariatinia Z. Pharmaceutical applications of chitosan. Advances in Colloid and Interface Science. 2019 Jan;263:131–94.
2. 2. Sahoo D, Sahoo S, Mohanty P, Sasmal S, Nayak PL. Chitosan: a New Versatile Bio-polymer for Various Applications. Designed Monomers and Polymers. 2009 Jan;12(5):377–404.
3. 3. Barbosa MA, Gonçalves IC, Moreno PMD, Gonçalves RM, Santos SG, Pêgo AP, et al. 2.13 Chitosan. In: Comprehensive Biomaterials II [Internet]. Elsevier; 2017 [cited 2021 Dec 11]. p. 279–305. ISBN: 978-0-08-100692-4.
4. 4. Oyervides-Muñoz E, Pollet E, Ulrich G, de Jesús Sosa-Santillán G, Avérous L. Original method for synthesis of chitosan-based antimicrobial agent by quaternary ammonium grafting. Carbohydrate Polymers. 2017 Feb;157:1922–32.
5. 5. Ünlü C, Pollet E, Avérous L. Original Macromolecular Architectures Based on poly(ε-caprolactone) and poly(ε-thiocaprolactone) Grafted onto Chitosan Backbone. IJMS. 2018 Nov 29;19(12):3799.
6. 6. Mino G, Kaizerman S. A new method for the preparation of graft copolymers. Polymerization initiated by ceric ion redox systems. J Polym Sci. 1958 Aug;31(122):242–3.
7. 7. Atici OG, Akar A, Ayar Y, Mecit O. Synthesis of block copolymers via redox polymerization. J Appl Polym Sci. 1999 Feb 28;71(9):1385–95.
8. 8. Kalaoğlu Öİ, Ünlü CH, Galioğlu Atıcı O. Synthesis, characterization and electrospinning of corn cob cellulose-graft-polyacrylonitrile and their clay nanocomposites. Carbohydrate Polymers. 2016 Aug;147:37–44.

9. 9. Pottenger CR, Johnson DC. Mechanism of cerium (IV) oxidation of glucose and cellulose. J Polym Sci A-1 Polym Chem. 1970 Feb;8(2):301–18.
10. 10. Ünlü CH, Öztekin NS, Atıcı OG. Synthesis and thermal characterization of xylan-graft-polyacrylonitrile. Carbohydrate Polymers. 2012 Oct;90(2):1120–6.
11. 11. Zohuriaan-Mehr M. Advances in Chitin and Chitosan Modification through Graft Copolymerization: A Comprehensive Review. Iranian Polymer Journal. 2005;14(3):235–65.
12. 12. Bulut E. Ibuprofen microencapsulation within acrylamide-grafted chitosan and methylcellulose interpenetrating polymer network microspheres: Synthesis, characterization, and release studies. Artificial Cells, Nanomedicine, and Biotechnology. 2015 Mar 6;1–11.
13. 13. Bhattarai N, Gunn J, Zhang M. Chitosan-based hydrogels for controlled, localized drug delivery. Advanced Drug Delivery Reviews. 2010 Jan;62(1):83–99.
14. 14. Martinez-Ruvalcaba A, Sanchez-Diaz JC, Becerra F, Cruz-Barba LE, Gonzalez-Alvarez A. Swelling characterization and drug delivery kinetics of polyacrylamide-co-itaconic acid/chitosan hydrogels. Express Polym Lett. 2009;3(1):25–32.
15. 15. Prabaharan M. Review Paper: Chitosan Derivatives as Promising Materials for Controlled Drug Delivery. J Biomater Appl. 2008 Jul;23(1):5–36.
16. 16. Wang L, Jian Y, Le X, Lu W, Ma C, Zhang J, et al. Actuating and memorizing bilayer hydrogels for a self-deformed shape memory function. Chem Commun. 2018;54(10):1229–32.
17. 17. Scholtan von W. Molekulargewichtsbestimmung von Polyacrylamid mittels der Ultrazentrifuge. Makromol Chem. 1954;14(1):169–78.
18. 18. Pamies R, Hernández Cifre JG, del Carmen López Martínez M, García de la Torre J. Determination of intrinsic viscosities of macromolecules and nanoparticles. Comparison of single-point and dilution procedures. Colloid Polym Sci. 2008 Sep;286(11):1223–31.
19. 19. Solomon OF, Ciuta IZ. Détermination de la viscosité intrinsèque de solutions de polymères par une simple détermination de la viscosité. J Appl Polym Sci. 1962 Nov;6(24):683–6.
20. 20. Akar A, Galioğlu O, Göçmen A, Sarac AS. Copolymer of ketonic resin–polyacrylonitrile. J Appl Polym Sci. 1990 Apr 20;39(8):1657–63.
21. 21. Galioğlu O, Soydan AB, Akar A, Saraç AS. Block/graft copolymer synthesis via ceric salt. Angew Makromol Chemie. 1994 Jan;214(1):19–28.
22. 22. Murugan R, Mohan S, Bigotto A. FTIR and polarised Raman spectra of acrylamide and polyacrylamide. Journal of the Korean Physical Society. 1998;32(4):505–12.