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

Abstract

Abstract: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.

pH-Responsive “Smart” Hydrogel for Controlled Delivery of Silver Nanoparticles to Infected Wounds

“…At predetermined time intervals, hydrogels were removed, the residual liquid from the surface was blotted and the weight was recorded. We hypothesized that at high pH, the carboxyl group of the methacrylic acid would be deprotonated and negatively charged, thereby generating electrostatic repulsion between molecular chains, resulting in a significant expansion of the hydrogel network [29]. In contrast, at lower pH, the carboxyl group would be protonated, resulting in a collapse of the hydrogel network and shrinkage.…”

An Updated Overview of the Emerging Role of Patch and Film-Based Buccal Delivery Systems

“…The stability of susceptible drugs in the oral environment was improved by employing cationic hydrogel polymers such as chitosan [143]. The pH sensitive hydrogel with remarkable swelling characteristics was also observed with most frequently used synthetic polymers, acrylamide and methacrylic acid [144]. A major limitation identified with nanoparticles is uncontrollable and inconsistent initial burst effect, which induces huge loss of drug resulting in subtherapeutic drug concentration.…”

Synthesis, classification and properties of hydrogels: their applications in drug delivery and agriculture

“…235 Abnormal physical function or medical conditions (including tumour environment) also change the pH in the body. 236 So, pH-responsive hydrogel systems can widely be used in the development of various drug delivery systems 221,237–239 keeping in mind the specific body part and its environment.…”