Evaluation of the degradation profile of biodegradable polymers in a dynamic in vitro model with artificial feline urine.

ObjectivesThis study aimed to evaluate the degradation profiles and mechanical properties of three absorbable polymers - poly(glycolide-co-trimethylene carbonate-co-epsilon-caprolactone) (PGTC), poly-p-dioxanone (PDO) and poly(glycolide-co-epsilon-caprolactone) (PGC) - envisioning the development of biodegradable ureteral stents in feline medicine.MethodsPGTC, PDO and PGC samples were exposed to artificial feline urine circulated through a dynamic system replicating ureteral flow at 38°C for 8 weeks. Degradation was evaluated through weekly measurements of mass loss and qualitative changes. Tensile strength, strain and stiffness were assessed at defined intervals (day 0, weeks 4, 6 and 7).ResultsPGC degraded completely by week 6, showing rapid loss of tensile strength but consistent stiffness. PGTC exhibited gradual degradation until week 8, at which point the material could no longer be handled because of structural weakening, with surface flaking visible microscopically. PDO did not fragment during manipulation or circulation, maintaining tensile strength over 8 weeks, although stiffness fluctuations and brittleness were observed.Conclusions and relevanceThe polymers showed distinct degradation and mechanical behaviours, providing options for different clinical scenarios. PGC, with rapid degradation, may suit short-term applications. PGTC, with gradual degradation and consistent mechanical properties, could serve intermediate applications. PDO, with slower degradation and prolonged tensile strength, appears suitable for longer-term use. These findings represent a step toward developing biodegradable ureteral stents for feline use, potentially simplifying postoperative management and avoiding stent removal. Biodegradable ureteral stents may improve the management of feline ureteral obstructions by eliminating secondary removal procedures. In this in vitro dynamic model, the polymers degraded in a controlled and predictable manner, without accumulation of debris or flow obstruction in the in vitro system. Future studies should assess whether similar behaviour occurs in smaller tubular structures similar to the feline ureter.