Controlled-release of antacids from biopolymer microgels under simulated gastric conditions: Impact of bead dimensions, pore size, and alginate/pectin ratio.

The highly acidic nature of the gastric fluids inside the human stomach can cause have health problems in certain individuals e.g., acid reflux and ulcers. Antacid-loaded biopolymer microgels can be used to control the acidity of the gastric fluids, which may be useful for developing functional foods to treat these problems. In this study, the impact of biopolymer microgel dimensions and composition on the dissolution rate of encapsulated antacid was determined under simulated gastric conditions. The microgels were formed by injecting antacid (magnesium hydroxide) and biopolymers (alginate or alginate/pectin) into a calcium chloride solution to promote cross-linking. Microgels of varying dimensions were formed using either a hand-held syringe or a vibrating nozzle encapsulation device with different nozzle sizes. The rate of antacid dissolution was measured using an automatic titration device (pH stat) that added HCl solution into the simulated gastric fluids to maintain a constant pH of 2.5. The antacid dissolution rate decreased with increasing microgel diameter (300 to 1660 μm) and decreasing pore size (0.8 to 2.0% alginate). The slowest dissolution rate was observed in microgels containing 80% alginate and 20% pectin, which may have been due to the impact of biopolymer composition on bead dimensions and pore size. The results of this study may be useful for the design of biopolymer microgels that can control the release of antacids in the stomach, thereby leading to better control over the pH of the gastric fluids.