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Earl, Emily Elizabeth

University of British Columbia

Over the past 30 years, treatments for heartburn have primarily remained unchanged. Current medication focuses on increasing the pH of gastric reflux by altering the overall pH of gastric fluid. This is accomplished by using neutralizing agents or by impairing the body’s ability to produce gastric acid. While these methods are effective at providing symptom management, they can cause undesired side effects and do not specifically target the gastric acid pocket: a highly acidic layer of gastric acid that remains stagnant at the top of the stomach. This thesis explores the development of an alternative technique to treat heartburn that focuses on relocating the contents of the gastric acid pocket rather than neutralizing it. In order to effectively perform this relocation, high-density chitosan-based superporous hydrogels were developed to displace the fluid in the gastric acid pocket by quickly absorbing the contents and sinking to the bottom of the stomach, away from the esophagus. The efficacy of the hydrogels was determined based on four main factors: swelling ability, equilibrium swelling time, swollen density, and biocompatibility. Two main methods of hydrogel formation were compared: the gas blowing method and the freeze-drying method. Within these two methods, a variety of hydrogel formulations were prepared in which the concentrations of polymers, crosslinking agents, and high-density materials were varied to optimize the hydrogel for maximum swelling ability. Biocompatible ceramics such as titanium dioxide and zirconium dioxide were used as the high- density materials in the hydrogel, and their biocompatibility was confirmed through cell cytotoxicity studies. An optimal hydrogel formulation was developed using the freeze-drying procedure paired with density adaptation from zirconium dioxide. This formulation is capable of swelling more than 25 times its initial mass in simulated gastric fluid while maintaining a swollen density higher than that of gastric content. With this swelling ability, an estimated amount of 4 grams of hydrogel material would be required to relocate the entirety of the gastric acid pocket, outlining the potential of this technique for further study regarding heartburn management.

Text

2023-12-20

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/80525

Mechanical Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/