title: An alginate-antacid formulation localizes to the acid pocket to reduce acid reflux in patients with gastroesophageal reflux disease.
abstract: OBJECTIVE
  Alginate rafts (polysaccharide polymers that precipitate into a low-density viscous gel when they contact gastric acid) have been reported to form at the acid pocket, an unbuffered pool of acid that floats on top of ingested food and causes postprandial acid reflux. We studied the location of an alginate formulation in relation to the acid pocket and the corresponding effects on reflux parameters and acid pocket positioning in patients with gastroesophageal reflux disease (GERD).
  
  
  METHODS
  We randomly assigned patients with symptomatic GERD and large hiatal hernias to groups who were given either (111)In-labeled alginate-antacid (n = 8, Gaviscon Double Action Liquid) or antacid (n = 8, Antagel) after a standard meal. The relative positions of labeled alginate and acid pocket were analyzed for 2 hours by using scintigraphy; reflux episodes were detected by using high-resolution manometry and pH-impedance monitoring.
  
  
  RESULTS
  The alginate-antacid label localized to the acid pocket. The number of acid reflux episodes was significantly reduced in patients receiving alginate-antacid (3.5; range, 0-6.5; P = .03) compared with those receiving antacid (15; range, 5-20), whereas time to acid reflux was significantly increased in patients receiving alginate-antacid (63 minutes; range, 23-92) vs those receiving antacid (14 minutes; range, 9-23; P = .01). The acid pocket was located below the diaphragm in 71% of patients given alginate-antacid vs 21% of those given antacid (P = .08). There was an inverse correlation between a subdiaphragm position of the acid pocket and acid reflux (r = -0.76, P < .001).
  
  
  CONCLUSIONS
  In a study of 16 patients with GERD, we observed that the alginate-antacid raft localizes to the postprandial acid pocket and displaces it below the diaphragm to reduce postprandial acid reflux. These findings indicate the importance of the acid pocket in GERD pathogenesis and establish alginate-antacid as an appropriate therapy for postprandial acid reflux.
authors.affiliation: Department of Gastroenterology and Hepatology, Academic Medical Centre, Amsterdam, the Netherlands.
authors.forename: Wout O
authors.initials: WO
authors.lastname: Rohof
authors.forename: Roel J
authors.initials: RJ
authors.lastname: Bennink
authors.forename: Andre J P M
authors.initials: AJ
authors.lastname: Smout
authors.forename: Edward
authors.initials: E
authors.lastname: Thomas
authors.forename: Guy E
authors.initials: GE
authors.lastname: Boeckxstaens
mesh_terms: D000464:Alginates / Q000008:administration & dosage*; D000863:Antacids / Q000008:administration & dosage*; D004337:Drug Carriers / Q000008:administration & dosage*; D017097:Electric Impedance; D005764:Gastroesophageal Reflux / Q000188:drug therapy*; D020723:Glucuronic Acid / Q000008:administration & dosage; D006603:Hexuronic Acids / Q000008:administration & dosage; D006801:Humans; D008365:Manometry; D011877:Radionuclide Imaging; D016896:Treatment Outcome
chemical_list: D000464:Alginates; D000863:Antacids; D004337:Drug Carriers; D006603:Hexuronic Acids; D020723:Glucuronic Acid
keywords: Clinical Trial; EGJ; Esophagus; GERD; HRM; Heartburn; LES; PPI; esophagogastric junction; gastroesophageal reflux disease; high-resolution manometry; lower esophageal sphincter; proton pump inhibitor