Two placebo-controlled crossover studies in healthy subjects to evaluate gastric acid neutralization by an alginate–antacid formulation (Gaviscon Double Action)

Abstract

Objective: To investigate the intragastric acid neutralization activity of a combined alginate-antacid formulation.

Significance: Published studies have investigated the reflux-suppressing alginate component of Gaviscon Double Action (Gaviscon DA; RB, UK) but intragastric acid neutralization activity of the antacid component has not been evaluated in vivo.

Methods: Intragastric pH monitoring, using a custom-made 10-electrode catheter, was evaluated in a two-part exploratory study in healthy subjects; Part I (n = 6) tested suitability of the catheter using antacid tablets (Rennie; Bayer, Germany); Part II (n = 12) evaluated gastric acid neutralization activity of Gaviscon DA liquid (20 ml) versus placebo in fasted subjects using a randomized, open-label, crossover design. The primary endpoint was the percentage of time that intragastric pH ≥4 was measured during 30 min post-treatment. A confirmatory study of identical design was subsequently conducted (n = 20).

Results: Monitoring pH using the multielectrode catheter was a viable approach, directly detecting changes in intragastric pH following a single dose of antacid tablets. In the exploratory study, the percentage of time that pH ≥4 during 30 minutes post-treatment was 46.8% with Gaviscon DA liquid versus 4.7% with placebo (p = 0.0004). These findings were supported by the confirmatory study, where pH ≥4 was recorded 50.8% of the time with Gaviscon DA versus 3.5% with placebo (p = 0.0051). In this study, Gaviscon DA was safe and well tolerated.

Conclusions: These studies demonstrate the effective acid neutralizing capacity of Gaviscon DA versus placebo in healthy, fasted subjects. This adds to the evidence base for the combination of alginates and antacids.

Trial registration: EU Clinical Trials Register identifier: 2014-003158-15.

Trial registration: EU Clinical Trials Register identifier: 2016-000539-42.

Keywords:

• Alginate
• antacid
• crossover study
• healthy volunteers
• gastric acid

Acknowledgments

We would like to thank Chris Blythe (Synmed) and Ken McColl for their expertise around catheter design and Lisa O’Rourke for writing assistance.

Data availability

The data that support the findings of this study are openly available within the EU Clinical Trials Register at www.clinicaltrialsregister.eu, reference numbers [2014-003158-15 and 2016-000539-42].

Disclosure of interest

JW, VH, MF, and CC are employees of RB Healthcare Ltd. KA-E, JW, and IDD are employees of QPS-Netherlands, a CRO that performs phase I/II studies for several pharmaceutical companies and academic centers. MvH is a consultant for QPS Netherlands. The current study was commissioned and funded by RB Healthcare Ltd. Writing support was provided by Cello Health Cypher and funded by RB Healthcare Ltd.