Design and biopharmaceutical preclinical characterisation of a new thermosensitive hydrogel for the removal of gastric polyps.

BACKGROUND AND AIMS:Submucosal injection agents are widely used solutions in gastric polyp resection techniques. Currently, many different solutions are used in clinical practice, but most are not authorised for this use or are not biopharmaceutical characterised. The objective of this multidisciplinary work is to test the efficacy of a novel thermosensitive hydrogel designed specifically for this indication. METHODS:A mixture design of various components (Pluronic®, hyaluronic acid and sodium alginate) was carried out to select the combination with optimal properties for this use. Three final thermosensitive hydrogels were selected on which biopharmaceutical characterisation was performed and stability and biocompatibility were analysed. Efficacy in maintaining elevation was tested ex vivo on pig mucosa and in vivo in pigs RESULTS: The mixture design allowed selection of the ideal combinations of agents for the characteristics sought. The thermosensitive hydrogels studied showed high values of hardness and viscosity at 37 °C, maintaining good syringeability. One of them demonstrated superiority in maintaining polyp elevation in the ex vivo assay and non-inferiority in the in vivo assay. CONCLUSION:The thermosensitive hydrogel specifically designed for this use is promising both for its biopharmaceutical characteristics and for its demonstrated efficacy. This study lays the foundation for evaluating the hydrogel in humans.