Courtney M Cottone1, Sherry Lu1, Yi Xi Wu2, Kevin Guan1, Renai Yoon1, Luke Limfueco1, Tuyen Hoang3, Winston Ciridon4, Buddy D Ratner4, Kathleen R Johnson5, Roshan M Patel1, Jaime Landman1, Ralph V Clayman1. 1. Department of Urology, University of California, Irvine, Orange, CA, USA. 2. Pharmaceutical Sciences, University of California, Irvine, Irvine, California, USA. 3. Institute of Clinical and Translational Science, University of California, Irvine, Irvine, California, USA. 4. Department of Bioengineering and Chemical Engineering, University of Washington, Seattle, Washington, USA. 5. Department of Physical Sciences, University of California, Irvine, Irvine, California, USA.
Abstract
Introduction: Encrustation of implanted urinary tract devices is associated with significant morbidity. Pellethane® is a polyether-based compound noted for its strength, porosity, and resistance to solvents. We assessed Pellethane thermoplastic polyurethane (TPU) with and without surface coatings 2-hydroxyethyl methacrylate (HEMA) and tetraethylene glycol dimethyl ether (TETRA) for the potential to resist encrustation in an artificial urine environment. Materials and Methods: Samples of Pellethane TPU, HEMA Pellethane TPU, TETRA Pellethane TPU, and hydrogel-coated ureteral stent (Cook®) were suspended in a batch-flow model with an artificial urine solution (AUS). Every 48 hours for 90 days, 40% of the solution was replaced with fresh AUS. All samples were stored in a 37°C incubator. Subsequently, the samples were thoroughly dried for 48 hours before weighing. Scanning electron microscopy was used to assess the degree of encrustation. Nu-Attom Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to determine the precise compositions of the encrustation specifically with regard to calcium, magnesium, and phosphate. Results: At the conclusion of the 90-day trial, the samples were analyzed, and the average mass changes were as follows: stent 63.78%, uncoated Pellethane TPU 11.50%, HEMA-coated Pellethane TPU 2.90%, and TETRA-coated Pellethane TPU 0.60%. Pellethane TPU products, and specifically those coated with HEMA and TETRA, exhibited less average mass increase and a lesser propensity to form encrustation than the traditional urinary tract stent. The mass increases noted on coated Pellethane devices were primarily ionic, whereas that of the stent was not. Conclusion: Pellethane, particularly with an HEMA-based preventative coating, may serve as a favorable alternative to traditional urinary stent material, providing its improved resistance to encrustation.
Introduction: Encrustation of implanted urinary tract devices is associated with significant morbidity. Pellethane® is a polyether-based compound noted for its strength, porosity, and resistance to solvents. We assessed Pellethane thermoplastic polyurethane (TPU) with and without surface coatings 2-hydroxyethyl methacrylate (HEMA) and tetraethylene glycol dimethyl ether (TETRA) for the potential to resist encrustation in an artificial urine environment. Materials and Methods: Samples of PellethaneTPU, HEMA PellethaneTPU, TETRA PellethaneTPU, and hydrogel-coated ureteral stent (Cook®) were suspended in a batch-flow model with an artificial urine solution (AUS). Every 48 hours for 90 days, 40% of the solution was replaced with fresh AUS. All samples were stored in a 37°C incubator. Subsequently, the samples were thoroughly dried for 48 hours before weighing. Scanning electron microscopy was used to assess the degree of encrustation. Nu-Attom Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to determine the precise compositions of the encrustation specifically with regard to calcium, magnesium, and phosphate. Results: At the conclusion of the 90-day trial, the samples were analyzed, and the average mass changes were as follows: stent 63.78%, uncoated PellethaneTPU 11.50%, HEMA-coated PellethaneTPU 2.90%, and TETRA-coated PellethaneTPU 0.60%. PellethaneTPU products, and specifically those coated with HEMA and TETRA, exhibited less average mass increase and a lesser propensity to form encrustation than the traditional urinary tract stent. The mass increases noted on coated Pellethane devices were primarily ionic, whereas that of the stent was not. Conclusion:Pellethane, particularly with an HEMA-based preventative coating, may serve as a favorable alternative to traditional urinary stent material, providing its improved resistance to encrustation.