Comparative studies on characterization and effectiveness of various alginate-based raft-forming antacid products

Pharmacy Practice

  • Peerawas Kopongpanich1PharmD; Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
  • Sarunrus Senasuthum2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
  • Tanet Promnim2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
  • Takao Hayashi3Department of Pharmaceutical Sciences, Faculty of Pharmacy, Meiji Pharmaceutical University, Tokyo, Japan.
  • Kengo Wada3Department of Pharmaceutical Sciences, Faculty of Pharmacy, Meiji Pharmaceutical University, Tokyo, Japan.
  • Pakorn Suriyakriangkai2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
  • Worathat Thitikornpong4PhD; Department of Food and Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
  • Varin Titapiwatanakun5PhD; Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
  • Kitiyot Yotsombut6PhD; Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.

Volume 24 Issue 2 Pages 1-11

DOI: 10.18549/PharmPract.2026.2.3533

Abstract

Background: Gastroesophageal reflux disease develops from exposure of the esophagus to acidic refluxate from the stomach and duodenal bile. While a floating raft, in which calcium carbonate was the main antacid ingredient, is formed on top of the stomach fluid to provide a physical barrier against acid gastroesophageal reflux after ingesting alginate-based antacid products. Objective: This work aimed to test in vitro effectiveness of five alginate suspensions commercially available in the Thai market to understand their characteristics and behaviors in gastric conditions mimicking the human stomach. Methods: Five commercial alginate suspensions were tested under simulated gastric conditions (0.1 N HCl, 37 °C). Raft formation was assessed by recording onset time, volume, mass, and buoyancy. Raft strength was quantified using a texture analyzer with a penetration probe, while porosity was examined visually. Acid neutralization capacity (ANC) was measured by titration against 0.1 N HCl to pH 3.0, and neutralization duration was monitored over time. Correlations between raft characteristics and ANC were analyzed. Results: Rafts of products formed voluminously (64.9-83.8 mL, 39.8-46.4 g), porous and floating rafts within 0.4-6.3 min. Raft strength and neutralization duration was in the range of 13.3-29.9 g and 24-46 min, respectively. Marked differences were not evident in the acid neutralization capacity (ANC) values of the products (8.8-9.9 mEq). No correlation was observed between ANC and raft-forming capacity or duration of neutralization though raft structures could affect their neutralization profiles. Conclusion: The results demonstrated that formulation design and raw material sourcing could vary product performance. While the obtained values of in vitro effectiveness could be applied to set the specifications and characterization methods for developing new raft-forming formulations and products. Importantly, understanding raft characteristics could empower pharmacists to make informed recommendations, providing patients with improved symptom relief and management.

Keywords

  • Gastroesophageal reflux disease
  • Raft-forming formulation
  • Alginates
  • Antacid
  • Anti-reflux
Pharmacy Practice

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