A Novel In Vitro Model for Determining the Optimum pH and Dose Volume of New Liquid Alginate for Infant Reflux Suppression

BACKGROUND: Gastroesophageal reflux frequently occurs in infants from birth to 2 years and is characterised by reflux and regurgitation often occurring during or immediately after feeds. These reflux events can range in both frequency and severity, and as the reflux events increase, they become increasingly distressing for both the infant and the parent. The study aimed to characterise the properties of a new infant liquid alginate product, determining the optimum gastric pH and dose volume for maximum reflux suppressant activity. METHODS: An in vitro infant stomach model was designed and developed that allowed products to be assessed for their reflux suppression activity. The validation of the model was completed by three independent operators comparing a milk control with infant Gaviscon to evaluate the models’ robustness, reproducibility, and ease of use. The model was used to establish reflux suppression activity of a new liquid alginate infant formulation in comparison with a milk control. Suppression activity was assessed at varying doses and pH within a physiological range. RESULTS: The validation study demonstrated no significant difference in refluxate volumes for the milk control within each reflux event when comparing across the three individual operators. Similarly, no statistical differences were seen during the infant Gaviscon experiments, confirming the robustness and reproducibility of the model. Significant reflux suppression was seen across the pH range (except at pH 5.75); the pH most advantageous for reflux suppression was pH 5.25. The optimum dose volume for consistently suppressing reflux was shown to be 5 ml. An infant stomach model was designed for evaluating reflux suppression activity of a formulation of liquid alginate. The optimum gastric pH and dose volume for demonstrating significant reflux suppression and the thickening of formula milk by the infant liquid alginate formulation were established. CONCLUSION: This study confirms the mode of action of the alginate formula, demonstrating a superior reduction in the retrograde movement of in vitro gastric contents and volume of regurgitation. The study also demonstrates that optimal performance occurs in conditions that are in line physiologically with the target patient. Both actions compliment and support the efficacy of the alginate formulation as a reflux therapy agent.