Gastrointestinal dynamics of superabsorbent polymers: Insights from a murine model

Purpose Superabsorbent polymers (SAPs) are widely used materials that pose a risk of pediatric intestinal obstruction following accidental ingestion. However, in vivo gastrointestinal dynamics of SAPs remain unclear. Methods We developed a murine model to determine the temporal changes in SAP localization and size following ingestion. The results were compared with the in vitro behavior of SAPs. Additionally, the effects of the co-administration of water on SAP behavior in vivo were also assessed. Results In vitro , SAPs rapidly expanded within 1 h, and the extent of expansion was strongly influenced by pH and the composition of the solution. In vivo , SAPs enlarged more gradually, reaching maximum size in the cecum approximately 4 h after ingestion and subsequently shrinking during colonic passage until excretion, thereby reducing the risk of intestinal obstruction. Co-administration of water accelerated SAP expansion, delayed gastrointestinal transit, and increased particle size, particularly in the small intestine and cecum, suggesting that dietary and fluid management should be carefully considered in patients with accidental SAP ingestion. Conclusions SAP gradually expanded from the stomach to the small intestine and shrank during expulsion through the colon. The simultaneous administration of water accelerated SAP expansion and delayed gastrointestinal transit.