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Clinical Testing of Occupational Glove Sensitivity
Published in Robert N. Phalen, Howard I. Maibach, Protective Gloves for Occupational Use, 2023
The chemicals found to be causes of occupational allergic contact dermatitis,80 in relation to their penetration through gloves, are acrylate compounds in dental professionals,81 ammonium thioglycolate in hairdressers,82 acrylamide in a laboratory technician,83 and an epoxysilane compound84 in a patient who compounded polyurethane and silicone resins.
Designing Biomaterials for Regenerative Medicine: State-of-the-Art and Future Perspectives
Published in Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon, Tissue Engineering Strategies for Organ Regeneration, 2020
Zohreh Arabpour, Mansour Youseffi, Chin Fhong Soon, Naznin Sultana, Mohammad Reza Bazgeir, Mozafari Masoud, Farshid Sefat
Polyurethanes (PUs) are popular because of their hardness, durability, biocompatibility, and stability in biological systems. In addition, Polyurethanes were demonstrated to improve cell adhesion and proliferation without any side effects (Phan et al. 2005). Conventionally, PUs have been used as permanent and inert materials in catheters, heart valves and vascular grafts (Santerre et al. 2005).
Seat Cushions
Published in J G Webster, Prevention of Pressure Sores, 2019
These foams are less expensive than most other materials because they are readily available in bulk quantities. Higher density polyurethane foams can be carved into specific contours that conform to the patient’s buttocks. The main drawback to polyurethane foams is that they do not endure much environmental aging (Noble et al 1983). Most foams last about six months before losing a significant amount of elasticity. Protective covers are necessary to extend the lifetime of foam cushions. Rulings in California and Boston by fire officials have restricted the use of traditional foams for wheelchair cushions for safety purposes (Krouskop et al 1986a).
Drug eluting implants in pharmaceutical development and clinical practice
Published in Expert Opinion on Drug Delivery, 2021
Ashley R. Johnson, Seth P. Forster, David White, Graciela Terife, Michael Lowinger, Ryan S. Teller, Stephanie E. Barrett
Commonly used polyols include di-hydroxyl terminated polyesters, poly(ethers), and poly(carbonates) in the molecular weight range of 1000 to 5000 Da. Poly(ester)-based poly(urethanes) often have good mechanical strength and thermal stability. They are, however, susceptible to hydrolysis of the ester linkage, resulting in the production of biodegradable poly(urethanes) with long degradation times. Poly(ether)-based poly(urethanes), on the other hand, have improved hydrolytic stability and exhibit more flexibility, but can be susceptible to oxidative and thermal degradation. For this reason, poly(ether)-based poly(urethanes) are typically stored in the presence of oxidative stabilizers; lubricants and thermal stabilizers are also added to extrudable thermoplastic polyurethanes. Of note, polyethylene oxide based poly(urethanes) are particularly relevant to pharmaceutical applications due their ability to take up water and create pores that enable drug diffusion [64,112].
Antithrombogenic peripherally inserted central catheters: overview of efficacy and safety
Published in Expert Review of Medical Devices, 2019
Amanda J. Ullman, AndreW. C. Bulmer, Tim R. Dargaville, Claire M. Rickard, Vineet Chopra
PICCs have evolved substantially since their introduction in the 1970s by Verne Hoshal and Millie Lawson [10]. Key changes include improvement in catheter material, design, and configuration. The first-generation PICCs were made of silicone-based polymers – thought to be more durable and dependable than non-silicone rubbers. However, this was not the case and silicone PICCs exhibited many problems including rupture of the catheter wall and local reactions along the vessel wall. These local reactions – ranging from mild irritation to phlebitis – often led to premature device removal and painful complications for patients [11]. In the early 1980s, polyurethane-based materials were introduced as a means to reduce these complications. However, first-generation polyurethane devices were associated with many of these same complications including phlebitis and venous irritation. Third-generation polyurethane materials (currently used in most PICCs) have provided the optimal blend of patient acceptance and durability. These materials, in turn, can also withstand high-pressure injections – leading to the term ‘POWER PICCs’ being used for devices compatible with radiographic injectors, for example [12].
Dural sealants for the management of cerebrospinal fluid leakage after intradural surgery: current status and future perspectives
Published in Expert Review of Medical Devices, 2019
Ahmet Kinaci, Tristan P.C. Van Doormaal
Polyurethanes are synthetic polymers in which the mechanical properties, biocompatibility, and biodegradability are determined by its composition. Polyurethanes are formed via a reaction between a diisocyanate and a diol. Isocyanates adhesives adhere covalently to the underlying tissue in the presence of water through the formation of urea bond with amines available in the underlying tissue [8]. The major disadvantage of the commonly used polyurethanes is that they are toxic and not readily biodegradable. However, the use of aliphatic isocyanates instead of aromatic isocyanates eliminates toxicity. By incorporating hydrolytically degradable esters bonds by using monomers such as lactic acid or caprolactone enables the development of biodegradable polyurethanes [22,23].