Duration of adhesion of swallowed alginates to distal oesophageal mucosa: implications for topical therapy of oesophageal diseases.

BACKGROUND

We have previously shown, ex vivo, that alginate solutions can have a topical protective effect on oesophageal mucosal biopsies exposed to simulated gastric juice. Oesophageal mucosal impedance can measure the duration of mucosal adherence of ionic solutions since the impedance drops when the solution is present, and rises to baseline as the solution clears.

AIM: To investigate the in vivo duration of adhesion of swallowed alginate solution to distal oesophageal mucosa.

METHODS

We studied 20 healthy volunteers and 10 patients with heartburn. A pH-impedance catheter was inserted, and baseline distal channel oesophageal impedance measured. Healthy volunteers received 10 mL of either sodium alginate (Gaviscon Advance), Gaviscon placebo (no alginate) or viscous slurry (saline mixed with sucralose), given in a randomised, single-blinded order over three visits. Patients received either sodium alginate or placebo on two visits. Initial impedance drop was measured, then 1-minute mean impedance was measured each minute until ≥75% recovery to baseline.

RESULTS

In healthy volunteers, sodium alginate adhered to the oesophageal mucosa for longer than placebo or viscous slurry (10.4 [8.7] minutes vs 1.1 [1.6] vs 3.6 [4.0], P < 0.01). In patients, sodium alginate adhered to the oesophageal mucosa for longer than placebo (9.0 (5.4) vs 3.7 (4.1), P < 0.01).

CONCLUSIONS

Sodium alginate solution adhered to the oesophageal mucosa for significantly longer than placebo or viscous slurry. This demonstrates that alginates could confer a protective benefit due to mucoadhesion and can be a basis for further development of topical protectants and for topical drug delivery in oesophageal disease.