Alginate Raft Formulations

Heartburn and Acid Reflux Cure Program

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Heartburn is one of the commonly experienced gastrointestinal symptoms. In fact it is the primary symptom of gastro-oesophageal reflux disease (GERD).45 The symptoms emerge, most often, following oesophageal influx of gastric acid. Thus, heartburn is strongly correlated with acidification of the oesophagus. The heartburn symptoms usually emerge in individuals after meals or nocturnally, often followed by burning substernal pain. The phenomena of gastrointestinal reflux and regurgitation are also clinical disorders frequently observed in infants and children.46 High incidence heartburn has also been observed in asthmatic patients47 and pregnant women on a daily basis.48

Alleviation of symptoms in these cases comes with alginate-based medication. Traditional medication includes antacids, containing Al(OH)3, AlPO4 or combinations thereof with Mg(OH)2 and magnesium trisilicate,49 characterized by a rapid onset in their action. Antacids raise the intragastric pH within minutes and offer relief of the heartburn symptoms. H2-receptor antagonists can also be used as nonprescription medication (with characteristic examples of H2-antagonists being Cimetidine®, Ranitidine®, Famotidine®, etc.), effectively controlling heartburn. These require systemic absorption for their action. Thus, they have a longer delay for the onset of their acid neutralization action, a disadvantage compared to antacids.50

Effective pharmaceuticals, combining the advantages of both, are alginate-based raft formulations. Alginates are natural polysaccharide polymers isolated from brown seaweed (Phaeophyceae) (Figure 4.2).

Algin Mannuronic Acid

Figure 4.2 Alginic acids are linear unbranched polymers containing ,0-(1-4)-linked D-mannuronic acid (m) and a-(1-4)-linked L-guluronic acid (g) monomers

Figure 4.2 Alginic acids are linear unbranched polymers containing ,0-(1-4)-linked D-mannuronic acid (m) and a-(1-4)-linked L-guluronic acid (g) monomers

In the acidic environment of the stomach, alginate salts and alginic acids precipitate to form a low-density viscous gel. The gel forms immediately upon contact with gastric acid. The marketed formulations often vary in composition (Gaviscon®), with the commonest form containing alginic acid, sodium bicarbonate, magnesium trisilicate and Al(OH)3. The latter agent is a well-known constituent of antacid preparations frequently used to counteract gastric acid secretion. This component appears to play a significant role in the action of the alginate-based drug(s).51

Upon contact of the medication with gastric acid, formation of a gel matrix takes place. Bicarbonate included in the formulation is trapped in the assembled 'eggbox' structure and leads to the generation of CO2 gas. The gas bubbles entrapped in the gel matrix convert it into foam and provide buoyancy, which allows the gel to float on the surface of the gastric contents, much like a raft on water, while concurrently providing neutralizing capacity. The raft physically acts as a barrier to gastric acid reflux and moves into the oesophagus during reflux. It essentially acts as a mobile neutralizing sealant in the oesopha-geal space when the gastric pressure is high. When the pressure drops, the raft is lowered back into the stomach area.

Studies conducted in vitro have looked into the interplay of visco-elastic raft strength and neutralizing capacity of raft formulations in the case of aluminum antacids. It was found that Al(OH)3 increases the neutralization profile of the raft, supporting the idea that the antacid-associated activity can be trapped into the raft of the gel matrix. That effect, however, results in a parallel reduction of the raft strength.52 Alginate-based antacids combine the advantages of rapid onset of relief, brought about by antacids, while concurrently offering significantly longer duration of action compared to conventional antacids. Finally, studies on variably formulated alginate raft preparations suggest that the generated CO2 from the bicarbonate along with antacid components, like Al(OH)3, within a specific formulation53 stay trapped in the assembled foaming raft, effectively providing it with lasting neutralization capacity.

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Herbal Remedies For Acid Reflux

Herbal Remedies For Acid Reflux

Gastroesophageal reflux disease is the medical term for what we know as acid reflux. Acid reflux occurs when the stomach releases its liquid back into the esophagus, causing inflammation and damage to the esophageal lining. The regurgitated acid most often consists of a few compoundsbr acid, bile, and pepsin.

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