{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T16:17:12Z","timestamp":1791476232881,"version":"4.3.4"},"reference-count":68,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,1,9]],"date-time":"2022-01-09T00:00:00Z","timestamp":1641686400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Taif University Researchers Supporting Program, Taif University, Saudi Arabia.","award":["TURSP-2020\/269"],"award-info":[{"award-number":["TURSP-2020\/269"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>This project aims to synthesize and characterize the pH-sensitive controlled release of 5-fluorouracil (5-FU) loaded hydrogels (5-FULH) by polymerization of acrylamide (AM) and acrylic acid (AA) in the presence of glutaraldehyde (GA) as a crosslinker with ammonium persulphate as an initiator. The formulation\u2019s code is named according to acrylamide (A1, A2, A3), acrylic acid (B1, B2, B3) and glutaraldehyde (C1, C2, C3). The optimized formulations were exposed to various physicochemical tests, namely swelling, diffusion, porosity, sol gel analysis, and attenuated total reflection-Fourier transform infrared (ATR-FTIR). These 5-FULH were subjected to kinetic models for drug release data. The 5-FU were shown to be soluble in distilled water and phosphate buffer media at pH 7.4, and sparingly soluble in an acidic media at pH 1.2. The ATR-FTIR data confirmed that the 5-FU have no interaction with other ingredients. The lowest dynamic (0.98 \u00b1 0.04% to 1.90 \u00b1 0.03%; 1.65 \u00b1 0.01% to 6.88 \u00b1 0.03%) and equilibrium swelling (1.85 \u00b1 0.01% to 6.68 \u00b1 0.03%; 10.12 \u00b1 0.02% to 27.89 \u00b1 0.03%) of formulations was observed at pH 1.2, whereas the higher dynamic (4.33 \u00b1 0.04% to 10.21 \u00b1 0.01%) and equilibrium swelling (22.25 \u00b1 0.03% to 55.48 \u00b1 0.04%) was recorded at pH 7.4. These findings clearly indicated that the synthesized 5-FULH have potential swelling characteristics in pH 6.8 that will enhance the drug\u2019s release in the same pH medium. The porosity values of formulated 5-FULH range from 34% to 62% with different weight ratios of AM, AA, and GA. The gel fractions data showed variations ranging from 74 \u00b1 0.4% (A1) to 94 \u00b1 0.2% (B3). However, formulation A1 reported the highest 24 \u00b1 0.1% and B3 the lowest 09 \u00b1 0.3% sol fractions rate among the formulations. Around 20% drug release from the 5-FULH was found at 1 h in an acidic media (pH1.2), whereas &gt;65% of drug release (pH7.4) was observed at around 25 h. These findings concluded that GA crosslinked 5-FU loaded AM and AA based hydrogels would be a potential pH-sensitive oral controlled colon drug delivery carrier.<\/jats:p>","DOI":"10.3390\/gels8010047","type":"journal-article","created":{"date-parts":[[2022,1,9]],"date-time":"2022-01-09T20:29:26Z","timestamp":1641760166000},"page":"47","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":41,"title":["Synthesis and Characterization of Acrylamide\/Acrylic Acid Co-Polymers and Glutaraldehyde Crosslinked pH-Sensitive Hydrogels"],"prefix":"10.3390","volume":"8","author":[{"given":"Munir Ahmad","family":"Khan","sequence":"first","affiliation":[{"name":"Department of Pharmaceutics, Faculty of Pharmacy, Gomal University, Dera Ismail Khan 29050, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4874-1169","authenticated-orcid":false,"given":"Abul Kalam","family":"Azad","sequence":"additional","affiliation":[{"name":"Pharmaceutical Technology Unit, Faculty of Pharmacy, AIMST University, Bedong 08100, Kedah, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Muhammad","family":"Safdar","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutics, Faculty of Pharmacy, Gomal University, Dera Ismail Khan 29050, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3232-0258","authenticated-orcid":false,"given":"Asif","family":"Nawaz","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutics, Faculty of Pharmacy, Gomal University, Dera Ismail Khan 29050, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Muhammad","family":"Akhlaq","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutics, Faculty of Pharmacy, Gomal University, Dera Ismail Khan 29050, Pakistan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pijush","family":"Paul","sequence":"additional","affiliation":[{"name":"Department of Pharmacy, Gono Bishwabidyalay, Mirzanagar, Savar, Dhaka 1344, Bangladesh"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Md. Kamal","family":"Hossain","sequence":"additional","affiliation":[{"name":"Institute of Health and Sports, Victoria University, Melbourne 3011, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6099-5693","authenticated-orcid":false,"given":"Md. Habibur","family":"Rahman","sequence":"additional","affiliation":[{"name":"Department of Global Medical Science, Wonju College of Medicine, Yonsei University, Wonju 26426, Gangwon-do, Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5324-0014","authenticated-orcid":false,"given":"Roua S.","family":"Baty","sequence":"additional","affiliation":[{"name":"Department of Biotechnology, College of Science, Taif University, P.O. 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Release"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1007\/s40005-017-0304-1","article-title":"Mesalamine-loaded alginate microspheres filled in enteric coated HPMC capsules for local treatment of ulcerative colitis: In vitro and in vivo characterization","volume":"48","author":"Patole","year":"2018","journal-title":"J. Pharm. Investig."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"102532","DOI":"10.1016\/j.jddst.2021.102532","article-title":"Colorectal cancer: A comprehensive review based on the novel drug delivery systems approach and its management","volume":"63","author":"Hani","year":"2021","journal-title":"J. Drug Deliv. Sci. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1117","DOI":"10.1016\/j.nano.2015.02.018","article-title":"Advances in oral nano-delivery systems for colon targeted drug delivery in inflammatory bowel disease: Selective targeting to diseased versus healthy tissue","volume":"11","author":"Hua","year":"2015","journal-title":"Nanomed. Nanotechnol. Biol. Med."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Lee, S.H., Bajracharya, R., Min, J.Y., Han, J.-W., Park, B.J., and Han, H.-K. (2020). Strategic Approaches for Colon Targeted Drug Delivery: An Overview of Recent Advancements. Pharmaceutics, 12.","DOI":"10.3390\/pharmaceutics12010068"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Bignotti, F., Baldi, F., Grassi, M., Abrami, M., and Spagnoli, G. (2021). Hydrophobically-Modified PEG Hydrogels with Controllable Hydrophilic\/Hydrophobic Balance. 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Res."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1503","DOI":"10.1016\/j.polymer.2003.12.040","article-title":"Structure and swelling of poly (acrylic acid) hydrogels: Effect of pH, ionic strength, and dilution on the crosslinked polymer structure","volume":"45","author":"Elliott","year":"2004","journal-title":"Polymer"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2805","DOI":"10.1007\/s10856-010-4134-1","article-title":"Preparation and characterization of hybrid pH-sensitive hydrogels of chitosan-coacrylic acid for controlled release of verapamil","volume":"21","author":"Ranjha","year":"2010","journal-title":"J. Mater. Sci. Mater. Med."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Akhlaq, M., Azad, A.K., Ullah, I., Nawaz, A., Safdar, M., Bhattacharya, T., Uddin, A.B., Abbas, S.A., Mathews, A., and Kundu, S.K. (2021). Methotrexate-loaded gelatin and polyvinyl alcohol (Gel\/PVA) hydrogel as a pH-sensitive matrix. Polymers, 13.","DOI":"10.3390\/polym13142300"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Malviya, R., Sundram, S., Fuloria, S., Subramaniyan, V., Sathasivam, K.V., Azad, A.K., Sekar, M., Kumar, D.H., Chakravarthi, S., and Porwal, O. (2021). Evaluation and Characterization of Tamarind Gum Polysaccharide: The Biopolymer. Polymers, 13.","DOI":"10.3390\/polym13183023"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"54","DOI":"10.3109\/1061186X.2012.725406","article-title":"pH-andthermo-sensitivepluronic\/poly(acrylic acid) in situ hydrogels for sustained release of an anticancer drug","volume":"21","author":"Lo","year":"2013","journal-title":"J. Drug Target."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1921","DOI":"10.1007\/s10856-007-3268-2","article-title":"Evaluation of water sorption property and in vitro blood compatibility of poly(2-hydroxyethyl methacrylate) (PHEMA) based semi interpenetrating polymer networks (IPNs)","volume":"19","author":"Bajpai","year":"2008","journal-title":"J. Mater. Sci. Mater. Med."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1411","DOI":"10.1007\/s00396-006-1513-8","article-title":"Effect of surface polarity on wettability and friction coefficient of silicone rubber\/poly(acrylic acid) hydrogel composite","volume":"284","author":"Kheirandish","year":"2006","journal-title":"Colloid Polym. Sci."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Rizwan, M., Yahya, R., Hassan, A., Yar, M., Azzahari, A.D., Selvanathan, V., Sonsudin, F., and Abouloula, C.N. (2017). pH Sensitive Hydrogels in Drug Delivery: Brief History, Properties, Swelling, and Release Mechanism, Material Selection and Applications. Polymers, 9.","DOI":"10.3390\/polym9040137"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Sudhakar, K., Fuloria, S., Subramaniyan, V., Sathasivam, K.V., Azad, A.K., Swain, S.S., Sekar, M., Karupiah, S., Porwal, O., and Sahoo, A. (2021). Ultraflexible Liposome Nanocargo as a Dermal and Transdermal Drug Delivery System. Nanomaterials, 11.","DOI":"10.3390\/nano11102557"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"144","DOI":"10.1016\/j.ijpharm.2007.08.007","article-title":"Modifying the release of proxyphylline from PVA hydrogels using surface crosslinking","volume":"349","author":"Wu","year":"2008","journal-title":"Int. J. Pharm."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"417","DOI":"10.1016\/B978-0-08-055294-1.00037-4","article-title":"1.124-Polymer Films Using LbL Self-Assembly","volume":"1","author":"Kozlovskaya","year":"2011","journal-title":"Compr. Biomater."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1007\/BF02697513","article-title":"Kinetics of crosslinking reaction of PVA membrane with glutaraldehyde","volume":"11","author":"Kim","year":"1994","journal-title":"Korean J. Chem. Eng."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1016\/0922-338X(91)90231-5","article-title":"Reaction of glutaraldehyde with amino and thiol compounds","volume":"71","author":"Okuda","year":"1991","journal-title":"J. Ferment. Bioeng."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Khan, T.A., Azad, A.K., Fuloria, S., Nawaz, A., Subramaniyan, V., Akhlaq, M., Safdar, M., Sathasivam, K.V., Sekar, M., and Porwal, O. (2021). Chitosan-Coated 5-Fluorouracil Incorporated Emulsions as Transdermal Drug Delivery Matrices. Polymers, 13.","DOI":"10.3390\/polym13193345"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1016\/j.jcrpr.2017.02.002","article-title":"Nano drug delivery strategy of 5-fluorouracil for the treatment of colorectal cancer","volume":"4","author":"Chandran","year":"2017","journal-title":"J. Cancer Res. Pract."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1261","DOI":"10.1007\/s10570-013-9897-3","article-title":"Thermoresponsive N-vinyl caprolactam grafted sodium alginate hydrogel beads for the controlled release of an anticancer drug","volume":"20","author":"Swamy","year":"2013","journal-title":"Cellulose"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"12109","DOI":"10.1039\/c3ra47991a","article-title":"Novel pH switchable gelatin-based hydrogel for the controlled delivery of the anticancer drug 5-fluorouracil","volume":"4","author":"Anirudhan","year":"2014","journal-title":"RSC Adv."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1080\/00914037.2015.1074910","article-title":"Diffusion and Controlled Release Characteristics of Ph-Sensitive Poly(2-(Dimethyl Amino)ethyl Methacrylate-co-2-hydroxyethylacrylate) Hydrogels","volume":"65","author":"Eswaramma","year":"2016","journal-title":"Int. J. Polym. Mater. Polym. Biomater."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"106035","DOI":"10.1039\/C6RA16746B","article-title":"Physically crosslinked pH-responsive chitosan-based hydrogels with enhanced mechanical performance for controlled drug delivery","volume":"6","author":"Che","year":"2016","journal-title":"RSC Adv."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1016\/j.eurpolymj.2019.05.017","article-title":"Enzyme and pH responsive 5-flurouracil (5-FU) loaded hydrogels based on olsalazine derivatives for colon-specific drug delivery","volume":"118","author":"Ma","year":"2019","journal-title":"Eur. Polym. J."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Latif, M.S., Azad, A.K., Nawaz, A., Rashid, S.A., Rahman, M., Al Omar, S.Y., Bungau, S.G., Aleya, L., and Abdel-Daim, M.M. (2021). Ethyl Cellulose and Hydroxypropyl Methyl Cellulose Blended Methotrexate-Loaded Transdermal Patches: In Vitro and Ex Vivo. Polymers, 13.","DOI":"10.3390\/polym13203455"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"194","DOI":"10.4028\/www.scientific.net\/MSF.789.194","article-title":"Glutaraldehyde-Cross-Linked Poly(acrylic acid-co-acrylamide)\/Poly(vinyl alcohol) Superabsorbent Membranes","volume":"789","author":"Wang","year":"2014","journal-title":"Mater. Sci. Forum"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Suhail, M., Fang, C.W., Khan, A., Minhas, M.U., and Wu, P.C. (2021). Fabrication and In Vitro Evaluation of pH-Sensitive Polymeric Hydrogels as Controlled Release Carriers. Gels, 7.","DOI":"10.3390\/gels7030110"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1186\/s40199-015-0123-8","article-title":"Effect of ethylene glycol dimethacrylate on swelling and on metformin hydrochloride release behavior of chemically crosslinked pH\u2013sensitive acrylic acid\u2013polyvinyl alcohol hydrogel","volume":"23","author":"Akhtar","year":"2015","journal-title":"DARU J. Pharm. Sci."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Al-Tabakha, M.M., Khan, S.A., Ashames, A., Ullah, H., Ullah, K., Murtaza, G., and Hassan, N. (2021). Synthesis, Characterization and Safety Evaluation of Sericin-Based Hydrogels for Controlled Delivery of Acyclovir. Pharmaceuticals, 14.","DOI":"10.3390\/ph14030234"},{"key":"ref_35","first-page":"36","article-title":"Synthesis and Characterization of Crosslinked Hydrogel of Konkoli (Maesopsis eminii) Grafted Polymethylacrylamide for a Preliminary Study as an Insulin Delivery System","volume":"4","author":"Ugwu","year":"2016","journal-title":"J. Biosci. Med."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"012023","DOI":"10.1088\/1757-899X\/809\/1\/012023","article-title":"Effect of pH on Swelling Profile of Glutaraldehyde Crosslinked Adenanthera pavonina L. Galactomannan","volume":"Volume 809","author":"Cavalcante","year":"2020","journal-title":"IOP Conference Series: Materials Science and Engineering, Proceedings of the 5th International Conference on Architecture, Materials and Construction (ICAMC 2019), Lisbon, Portugal, 2\u20134 December 2019"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1007\/s13205-019-1720-x","article-title":"Modeling a pH-sensitive Zein-co-acrylic acid hybrid hydrogels loaded 5-fluorouracil and rutin for enhanced anticancer efficacy by oral delivery","volume":"9","author":"Kunjiappan","year":"2019","journal-title":"3 Biotech"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Shah, M.K., Azad, A.K., Nawaz, A., Ullah, S., Latif, M.S., Rahman, H., Alsharif, K.F., Alzahrani, K.J., El-Kott, A.F., and Albrakati, A. (2022). Formulation Development, Characterization and Antifungal Evaluation of Chitosan NPs for Topical Delivery of Voriconazole In Vitro and Ex Vivo. Polymers, 14.","DOI":"10.3390\/polym14010135"},{"key":"ref_39","first-page":"143","article-title":"Evaluation of crosslinked hydroxypropyl methylcellulose graft-methacrylic acid copolymer as extended-release oral drug carrier","volume":"49","author":"Ali","year":"2015","journal-title":"Cell. Chem. Technol."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"619","DOI":"10.1016\/j.radphyschem.2004.03.011","article-title":"Radiation synthesis and characterization of stimuli-sensitive chitosan\u2013polyvinyl pyrrolidone hydrogels","volume":"72","author":"Dergunov","year":"2005","journal-title":"Radiat. Phys. Chem."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1163\/138577210X509561","article-title":"A novel method to prepare 5-fluorouracil, an anti-cancer drug, loaded microspheres from poly (N-vinyl caprolactam-co-acrylamide) and controlled release studies","volume":"13","author":"Mundargi","year":"2010","journal-title":"Des. Monomers Polym."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1016\/S0168-3659(99)00176-5","article-title":"Glutaraldehyde crosslinked sodium alginate beads containing liquid pesticide for soil application","volume":"63","author":"Kulkarni","year":"2000","journal-title":"J. Control. Release"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"173","DOI":"10.1590\/S1984-82502011000100018","article-title":"pH-sensitive polyvinylpyrrolidone-acrylic acid hydrogels: Impact of material parameters on swelling and drug release","volume":"50","author":"Sohail","year":"2014","journal-title":"Braz. J. Pharm. Sci."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"460","DOI":"10.19113\/sdufbed.53790","article-title":"Synthesis and Characterization of 5-Fluorouracil-Loaded Glutaraldehyde Crosslinked Chitosan Hydrogels","volume":"20","year":"2016","journal-title":"S\u00fcleyman Demirel \u00dcniv. Fen Bilim. Enst. Derg."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"6851","DOI":"10.1016\/S0032-3861(01)00143-4","article-title":"pH\/temperature-responsive behaviors of semi-IPN and comb-type graft hydrogels composed of alginate and poly (N-isopropylacrylamide)","volume":"42","author":"Ju","year":"2001","journal-title":"Polymer"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"591","DOI":"10.1016\/j.carbpol.2010.08.022","article-title":"Analysis of soluble and insoluble fractions of alkali and subcritical water treated sugarcane bagasse","volume":"83","author":"Ju","year":"2011","journal-title":"Carbohydr. Polym."},{"key":"ref_47","doi-asserted-by":"crossref","unstructured":"Bashir, S., Teo, Y.Y., Naeem, S., Ramesh, S., and Ramesh, K. (2017). pH responsive N-succinyl chitosan\/Poly (acrylamide-co-acrylic acid) hydrogels and in vitro release of 5-fluorouracil. PLoS ONE, 12.","DOI":"10.1371\/journal.pone.0179250"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1016\/j.polymer.2016.03.045","article-title":"Synthesis, characterization, properties of N-succinyl chitosan-g-poly (methacrylic acid) hydrogels and in vitro release of theophylline","volume":"92","author":"Bashir","year":"2016","journal-title":"Polymer"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"567","DOI":"10.1002\/pat.226","article-title":"Swelling behaviors of polyelectrolyte hydrogels containing sulfonate groups","volume":"13","author":"Atta","year":"2002","journal-title":"Polym. Adv. Technol."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"763","DOI":"10.1002\/app.34470","article-title":"Removal of heavy metals from model wastewater by using carboxymehyl cellulose\/2-acrylamido-2-methyl propane sulfonic acid hydrogels","volume":"123","author":"Ali","year":"2012","journal-title":"J. Appl. Polym. Sci."},{"key":"ref_51","first-page":"481","article-title":"Investigation of swelling behavior and mechanical properties of a pH-sensitive superporous hydrogel composite","volume":"11","author":"Gupta","year":"2012","journal-title":"Iran. J. Pharm. Res."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"187961","DOI":"10.1155\/2015\/187961","article-title":"Synthesis and Characterization of Chemically Cross-Linked Acrylic Acid\/Gelatin Hydrogels: Effect of pH and Composition on Swelling and Drug Release","volume":"2015","author":"Bukhari","year":"2015","journal-title":"Int. J. Polym. Sci."},{"key":"ref_53","doi-asserted-by":"crossref","unstructured":"Azad, A.K., Al-Mahmood, S.M.A., Chatterjee, B., Wan Sulaiman, W.M.A., Elsayed, T.M., and Doolaanea, A.A. (2020). Encapsulation of black seed oil in alginate beads as a pH-sensitive carrier for intestine-targeted drug delivery: In vitro, in vivo and ex vivo study. Pharmaceutics, 12.","DOI":"10.3390\/pharmaceutics12030219"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1080\/00914037.2013.769165","article-title":"Studies on glutaraldehyde crosslinked chitosan hydrogel properties for drug delivery systems","volume":"62","author":"Mirzaei","year":"2013","journal-title":"Int. J. Polym. Mater. Polym. Biomater."},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"Suhail, M., Hsieh, Y.-H., Khan, A., Minhas, M.U., and Wu, P.-C. (2021). Preparation and In Vitro Evaluation of Aspartic\/Alginic Acid Based Semi-Interpenetrating Network Hydrogels for Controlled Release of Ibuprofen. Gels, 7.","DOI":"10.3390\/gels7020068"},{"key":"ref_56","doi-asserted-by":"crossref","unstructured":"Suhail, M., Khan, A., Rosenholm, J.M., Minhas, M.U., and Wu, P.-C. (2021). Fabrication and Characterization of Diclofenac Sodium Loaded Hydrogels of Sodium Alginate as Sustained Release Carrier. Gels, 7.","DOI":"10.3390\/gels7010010"},{"key":"ref_57","doi-asserted-by":"crossref","unstructured":"Akhlaq, M., Azad, A.K., Fuloria, S., Meenakshi, D.U., Raza, S., Safdar, M., Nawaz, A., Subramaniyan, V., Sekar, M., and Sathasivam, K.V. (2021). Fabrication of Tizanidine Loaded Patches Using Flaxseed Oil and Coriander Oil as a Penetration Enhancer for Transdermal Delivery. Polymers, 13.","DOI":"10.3390\/polym13234217"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"861","DOI":"10.1016\/j.ijbiomac.2021.07.019","article-title":"Electro-hydrodynamic assisted synthesis of lecithin-stabilized peppermint oil-loaded alginate microbeads for intestinal drug delivery","volume":"185","author":"Azad","year":"2021","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"663","DOI":"10.1080\/10601325.2020.1756319","article-title":"HPMC-coacrylic acid dexibuprofen once-daily oral hydrogels","volume":"57","author":"Akhlaq","year":"2020","journal-title":"J. Macromol. Sci. Part A"},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/j.ijbiomac.2019.02.031","article-title":"Chitosan based thermosensitive injectable hydrogels for controlled delivery of loxoprofen: Development, characterization and in-vivo evaluation","volume":"129","author":"Ahmad","year":"2019","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_61","first-page":"400","article-title":"Preparation and characterization of crosslinked acrylic acid\/hydroxypropyl methyl cellulose hydrogels for drug delivery","volume":"6","author":"Ranjha","year":"2014","journal-title":"Int. J. Pharm. Pharm. Sci."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"1345","DOI":"10.1002\/adma.200501612","article-title":"Hydrogels in Biology and Medicine: From Molecular Principles to Bionanotechnology","volume":"18","author":"Peppas","year":"2006","journal-title":"Adv. Mater."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1016\/S0939-6411(00)00090-4","article-title":"Hydrogels in pharmaceutical formulations","volume":"50","author":"Peppas","year":"2006","journal-title":"Eur. J. Pharm. Biopharm."},{"key":"ref_64","first-page":"2","article-title":"Preparation methods and structure of hydrogels","volume":"Volume 1","author":"Peppas","year":"1986","journal-title":"Hydrogels in Medicine and Pharmacy"},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"506","DOI":"10.1016\/j.ijbiomac.2019.04.005","article-title":"5-Fluorouracil loaded chitosan\/polyacrylic acid\/Fe3O4 magnetic nanocomposite hydrogel as a potential anticancer drug delivery system","volume":"132","author":"Mohammadi","year":"2019","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1007\/s10971-008-1750-z","article-title":"Methyl methacrylate-co-itaconic acid (MMA-co-IA) hydrogels for controlled drug delivery","volume":"47","author":"Ranjha","year":"2008","journal-title":"J. Sol-Gel Sci. Technol."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"021","DOI":"10.7324\/JAPS.2015.501204","article-title":"Synthesis of Novel Hydrogels based Poly(4-Hydroxyphenylazo-3-N-(4-hydroxyphenyl)maleimide) for Specific Colon Delivery of Chemotherapeutic Agent","volume":"5","author":"Reddy","year":"2015","journal-title":"J. Appl. Pharm. Sci."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"45886","DOI":"10.1002\/app.45886","article-title":"pH-sensitive polymeric particles as smart carriers for rebar inhibitors delivery in alkaline condition","volume":"135","author":"Feng","year":"2018","journal-title":"J. Appl. Polym. 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