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Open AccessArticle

Design of a Versatile pH-Responsive Hydrogel for Potential Oral Delivery of Gastric-Sensitive Bioactives

Wits Advanced Drug Delivery Platform Research Unit, Department of Pharmacy and Pharmacology, Faculty of Health Sciences, School of Therapeutics Sciences, University of the Witwatersrand, Johannesburg, 7 York Road, Parktown 2193, South Africa
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Polymers 2017, 9(10), 474; https://doi.org/10.3390/polym9100474
Received: 21 August 2017 / Revised: 25 September 2017 / Accepted: 25 September 2017 / Published: 27 September 2017
(This article belongs to the Special Issue Stimuli Responsive Polymers)
A pH-responsive hydrogel system was prepared by free radical polymerization of acrylamide and methyl acrylic acid in the presence of N-N′-methylene bisacrylamide. Sodium bicarbonate was further applied as a blowing agent, which afforded a porous hydrogel structure. The hydrogel system achieved a constant super swelling rate within simulated intestinal buffer (~4%/min) and remained relatively static within simulated gastric buffer (~0.8%/min). The hydrogel system was able to achieve matrix resilience greater than 30% under a relatively high strain of 40%. In addition, the hydrogel system demonstrated significant swelling properties in response to simulated intestinal environmental over 24 h, with contrasting characteristics in simulated gastric buffer. The hydrogel demonstrated type IV isotherm porosity characteristics, with remarkable MRI and SEM variations in gastric and intestinal simulated fluids. Drug loading was observed to be greater than 98% using theophylline as a prototype drug, evaluating its controlled release kinetics over 24 h. The hydrogel exhibited substantial pH-responsive activity, which could be used as a versatile platform for targeted release of gastric-sensitive therapeutics to the small intestine. View Full-Text
Keywords: acrylamide (Aam); methacrylic acid (MAA); stimuli-responsive drug delivery; pH-responsive hydrogel; free radical polymerization acrylamide (Aam); methacrylic acid (MAA); stimuli-responsive drug delivery; pH-responsive hydrogel; free radical polymerization
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MDPI and ACS Style

Hibbins, A.R.; Kumar, P.; Choonara, Y.E.; Kondiah, P.P.D.; Marimuthu, T.; Du Toit, L.C.; Pillay, V. Design of a Versatile pH-Responsive Hydrogel for Potential Oral Delivery of Gastric-Sensitive Bioactives. Polymers 2017, 9, 474.

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