Clinical and laboratory studies of the antacid and raft-forming properties of Rennie alginate suspension.
BACKGROUND
Acid pockets at the gastro-oesophageal junction escape buffering from meals in the stomach. Combining high-dose antacid with alginate may therefore be of benefit in gastro-oesophageal reflux disease.


OBJECTIVE
To characterize the antacid and raft-forming properties of Rennie alginate suspension (containing high-dose antacid and alginate; Bayer Consumer Care, Bladel, the Netherlands).


METHODS
The in vitro acid-neutralizing capacity of Rennie algniate was compared with Gaviscon (Reckitt Benckiser, Slough, UK) by pH-recorded HCl titration. Alginate raft weight formed in vitro at different pH was used to evaluate the pH dependency of raft formation with each product. A double-blind, placebo-controlled, randomized crossover study also compared the antacid activity of Rennie alginate vs. placebo in vivo using continuous intragastric pH monitoring in 12 healthy fasting volunteers.


RESULTS
Compared with Gaviscon, Rennie alginate had a higher acid-neutralizing capacity, greater maximum pH and longer duration of antacid activity in vitro. However, the two products produced comparable alginate rafts at each pH evaluated. In vivo, Rennie alginate provided rapid, effective and long-lasting acid neutralization, with an onset of action of <5 min, and duration of action of almost 90 min.


CONCLUSIONS
The dual mode of action of Rennie alginate offers an effective treatment option for mild symptomatic gastro-oesophageal reflux disease particularly considering recent findings regarding 'acid pockets'.
Academisch Medisch Centrum, Amsterdam, the Netherlands. g.n.tytgat@amc.uva.nl
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D000293:Adolescent; D000328:Adult; D000464:Alginates / Q000627:therapeutic use*; D000536:Aluminum Hydroxide / Q000627:therapeutic use; D000863:Antacids / Q000378:metabolism / Q000627:therapeutic use*; D002119:Calcium Carbonate / Q000627:therapeutic use*; D002254:Carbonates / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004338:Drug Combinations; D005260:Female; D005744:Gastric Acid / Q000378:metabolism; D005745:Gastric Acidity Determination; D005764:Gastroesophageal Reflux / Q000188:drug therapy; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000627:therapeutic use*; D008297:Male; D012824:Silicic Acid / Q000627:therapeutic use; D017693:Sodium Bicarbonate / Q000627:therapeutic use
D000464:Alginates; D000863:Antacids; D002254:Carbonates; D004338:Drug Combinations; D012824:Silicic Acid; D000536:Aluminum Hydroxide; C007829:alginate, aluminium hydroxide, magnesium trisilicate, sodium bicarbonate drug combination; C099689:Rennie; D017693:Sodium Bicarbonate; D002119:Calcium Carbonate; D008274:Magnesium