Pharmacokinetics and the effectiveness of pyrogen-free bioabsorbable wet adhesives.

Bioabsorbable materials are essential for advanced therapies, including surgical sealing, cell therapy, and drug delivery. Natural bioabsorbable materials, including collagen and hyaluronic acid, have better biocompatibility than synthetic bioabsorbable polymers; however, they are mainly derived from animals, presenting infection risks. Non-animal origin polymers have a lower molecular weight than those of animal origins. Their viscosity increases with increase in molecular weight, making endotoxin removal difficult. Here, using the phosphoryl chloride disposal method, we present a strategy for synthesizing pyrogen-free bioabsorbable adhesives with controlled molecular weight. Phosphopullulan, a polysaccharide derivative, had less than detectable endotoxin levels and controllable average molecular weight of approximately 300,000 to over 1,400,000. Furthermore, it is important to ensure the safety as well as efficacy of bio-implantable materials. We have evaluated the biosafety of polysaccharide derivatives we are developing, and have examined their cell phagocytosis and pharmacokinetics in vitro and in vivo, and have confirmed that they are safe. We have also evaluated their adhesion to wet tissue adhesions and confirmed that they leak less than existing materials.