Bioadhesive oesophageal bandages: protection against acid and pepsin injury.
The rate of acid and pepsin diffusion through solutions of sodium alginate was measured using in vitro techniques. Previous work has demonstrated that solutions of alginate may adhere to the oesophagus for up to 60 min; this work measured their ability to protect the oesophageal epithelial surface from damage caused by refluxed acid and pepsin. Franz diffusion cells were used to measure the rate of acid and pepsin diffusion through an alginate layer. The effect of the type of alginate, alginate concentration and depth of alginate applied were investigated. The rate of both acid and pepsin diffusion was significantly reduced (ANOVA analysis; P<0.05) in the presence of an alginate solution compared to the control. A 2% (w/v) alginate solution with a high guluronic acid component, in a layer of 0.44 mm depth, demonstrated the greatest reduction in acid diffusion with a permeation coefficient 14% than that of a control value. All three alginates demonstrated significant reductions in acid diffusion with both increasing depth and increasing concentration, as expected. Pepsin diffusion was also significantly reduced as the depth and concentration of applied alginate increased. This study demonstrates that an adhesive layer of alginate present within the oesophagus will limit the contact of refluxed acid and pepsin with the epithelial surface.
Tang
Man
M
Medicines Research Unit, Aston University, Aston Triangle, Birmingham B4 7ET, UK.
Dettmar
Peter
P
Batchelor
Hannah
H
D000464:Alginates / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D019540:Area Under Curve; D001684:Biological Dressings; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology; D004058:Diffusion / Q000187:drug effects; D004304:Dosage Forms; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004942:Esophagitis, Peptic / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control; D004947:Esophagus / Q000187:drug effects / Q000473:pathology; D005744:Gastric Acid / Q000378:metabolism*; D005753:Gastric Mucosa / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D005764:Gastroesophageal Reflux / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control; D006603:Hexuronic Acids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010434:Pepsin A / Q000009:adverse effects* / Q000378:metabolism*; D011522:Protons; D012996:Solutions / Q000737:chemistry; D013552:Swine; D014014:Tissue Adhesives / Q000737:chemistry / Q000493:pharmacokinetics / Q000627:therapeutic use*; D014783:Viscosity
D000464:Alginates; D004304:Dosage Forms; D006603:Hexuronic Acids; D011522:Protons; D012996:Solutions; D014014:Tissue Adhesives; C007896:guluronic acid; D010434:Pepsin A