The effect of calcium alginate on the neutralising properties of chitosan gels protecting the oesophageal mucosa

Gastroesophageal reflux disease is one of the most frequently diagnosed conditions in the modern world. It is characterised by repeated movement of stomach acid into the oesophagus, causing irritation and symptoms such as heartburn and regurgitation. Due to their short residence time on the mucous membrane surface, the emulsions used so far do not fulfil their role. This research aimed to examine the effect of calcium alginate on the properties of gels containing chitosan. For this purpose, hydrophilic gels were prepared and tested for pH, dynamic viscosity, and their ability to move in a model simulating conditions in the oesophagus. Alginates have been shown to affect the increase of pH and give the ability to neutralise acidic stomach content. As pH exceeded the upper physiological limit, chitosan offered the potential to restore pH to the physiological range. Its addition had an additional important feature - an increase in the dynamic viscosity of gel and adhesion, which would lead to better gel adhesion to the oesophagus. In summary, the addition of chitosan to methylcellulose gels containing calcium alginate positively influenced the pH, making it more suitable for the oesophagus, and enhanced the dynamic viscosity, allowing the gel to adhere to the mucous membrane surface for protective purposes against reflux.