Polyurethanes drug delivery applications

Biodegradable polyurethanes have been proposed and studied before (9-72). The difference in our study is the inclusion of a phosphoester linkage instead of the commonly used polyester component. This seems to provide more flexibility as the side chain of the phosphate or phosphonate can be varied. For controlled drug delivery applications, drugs can be linked to this site to form a pendant delivery system. Moreover, for certain medical applications, fast degradation rate is obtainable by the introduction of these hydrolyzable phosphoester bonds. With the LDI based polyurethanes, drugs or other compounds of interest can also be coupled to the ester side chain of the lysine portion. 

K. Saha, B.S. Butola, M. Joshi, Drug-loaded polyurethane/clay nanocomposite nanofibers for topical drug-delivery application, J. Appl. Polym. Sci. 131 (2014). 

This book brings together a thorough review of advances in properties and applications of polyurethanes for biomedical applications. The first set of chapters provides an important overview of the fundamentals of this material with chapters on properties and processing methods of polyurethanes. Further sections cover significant uses such as vascular, tissue engineering, and drug delivery applications. 

Ethylene vinyl acetate has also found major applications in drug delivery. These copolymers used in drug release normally contain 30-50 wt% of vinyl acetate. They have been commercialized by the Alza Corporation for the delivery of pilocarpine over a one-week period (Ocusert) and the delivery of progesterone for over one year in the form of an intrauterine device (Progestasert). Ethylene vinyl acetate has also been evaluated for the release of macromolecules such as proteins. The release of proteins form these polymers is by a porous diffusion and the pore structure can be used to control the rate of release (3). Similar nonbiodegradable polymers such as the polyurethanes, polyethylenes, polytetrafluoroethylene and poly(methyl methacrylate) have also been used to deliver a variety of different pharmaceutical agents usually as implants or removal devices. 

Sucrose acrylate derivatives can be converted into polymers and hydrogels that can be used as flocculants, water adsorbents, bioimplantables, and drug delivery devices (42). Sucrose ethers have applications as surfactants and surface coatings, and as feedstocks for synthesis of polyurethane foams and... 

Other Synthetic Biodegradable Polymers Although well investigated for drug delivery, polyorthoesters, polyurethanes, and polyamides have found limited application as nanoparticles. A report documents the synthesis and characterization of polyorthoester nanoparticles [105],... 

Poly(propylene oxide) is typically obtained by base catalyzed anionic polymerization of propylene oxide [12]. Both stereospecific and atactic forms are known. The polymer is used as a soft polyether unit in polyurethane elastomers and foams in polymer electrolytes as surfactants (lubricants, dispersants, antistatic agents, foam control agents) in printing inks, as solubilizers in hydraulic fluids, coolant compositions in various medical applications (protective bandages, drug delivery systems, organ preservation, dental compositions), etc. 

Among the many classes of polymeric materials now available for use as biomaterials, non-degradable, hydrophobic polymers are the most widely used. Silicone, polyethylene, polyurethanes, PMMA, and EVAc account for the majority of polymeric materials currently used in clinical applications. Consider, for example, the medical applications listed in Table A.l most of these applications require a polymer that does not change substantially during the period of use. This chapter describes some of the most commonly used non-degradable polymers that are used as biomaterials, with an emphasis on their use in drug delivery systems. 

As we shall see in Chapter 15, polyurethane is a polymer of choice for a wide variety of biomedical applications. Polyurethane is used extensively in the construction of devices such as vascular prostheses, membranes, catheters, plastic surgery, heart valves, and artificial organs. Polyurethanes are also used in drug delivery systems such as the sustained and controlled delivery of pharmaceutical agents, for example, caffeine and prostaglandin. ... 

Due to the special features mentioned above, siloxane amphiphiUc copolymers are used in a wide variety of applications including foam stabilization in plastic (polyurethane) foams, cosmetics, wetting, emulsification, lubrication and in antistatic agents, drug delivery and so forth. 

Vegetable oil-based hyperbranched polymers have considerable potential in biomedical applications. This is due to their unique structural characteristics along with their biodegradability and biocompatibiUty. Preliminary studies show that vegetable oil-based hyperbranched polyurethanes have the potential to be used as biomaterials in biomedical applications such as drug delivery systems, biomedical smart materials and catheters. ... 

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