Synthetic polymers Toxicity

In macromolecular dmg delivery systems, dmgs are attached to polymeric compounds, such as synthetic polymers [60], dendrimers [61], and antibodies [62], in order to enhance the delivery of the active substance to the diseased tissue and to reduce the toxicity to healthy tissue. The use of macromolecular delivery systems provides several advantages extension of the half-life of the dmg, the ability to introduce targeting moieties into the carrier, the possibility of triggered dmg release, and the aforementioned reduced cytotoxicity. 

Polymeric drugs are macromolecules that elicit biological activity (7). Many synthetic polymers are biologically inert. However, some exhibit toxicity, while others exhibit a wide range of therapeutic activities. There are three kinds of polymer drugs polycations, polyanions, and polynucleotides. 

The irradiation of polymers is widespread in many industries. For example, microlithography is an essential process in the fabrication of integrated circuits that involves the modification of the solubility or volatility of thin polymer resist films by radiation. The sterilization by radiation of medical and pharmaceutical items, many of which are manufactured from polymeric materials, is increasing. This trend arises from both the convenience of the process and the concern about the toxicity of chemical sterilants. Information about the radiolysis products of natural and synthetic polymers used in the medical industry is required for the evaluation of the safety of the process. 

Hydrogen cyanide has recently been recognized in significant concentrations in some fires, as a combustion product of wool, silk, and many synthetic polymers it may play a role in toxicity and deaths ftom smoke inhalation." ... 

While commercially available synthetic polymers are relatively nontoxic, the monomers vary greatly in toxicity. This points out the need for monomers and other potentially toxic chemicals to be removed from the polymers. Table 2 contains the time-weight average (TWA) for some monomers as cited by the United States Occupational Standards. For comparison, entries for some well-known toxic materials have been added. 

Synonyms methanal, methylene oxide, oxymethane Formula HCHO MW 30.03 CAS[50-00-0] constitutes about 50% of all aldehydes present in air released in trace quantities from pressed wood products, burning wood, and synthetic polymers and automobiles colorless gas at ambient conditions pungent suffocating odor liquefies at -19.5°C solidifies at -92°C density 1.07 (air = 1) very soluble in water, soluble in organic solvents readily polymerizes flammable, toxic, and carcinogenic (Patnaik, 1992). 

Among organic chemicals are included the majority of important industrial compounds, synthetic polymers, agricultural chemicals, biological materials, and most substances that are of concern because of their toxicities and other hazards. Pollution of the water, air, and soil environments by organic chemicals is an area of significant concern. 

Polyglycolide was one of the first synthetic polymers used as a degradable surgical suture [122]. Fig. 8 shows the glycolide monomer and polymer structures. This aliphatic polyester is biodegradable and exhibits negligible toxicity when implanted in tissue. It is also possible to fabricate a strong fiber of this polyester with satisfactory mechanical properties. 

Related to ionic liquids are substances known as deep eutectic solvents or mixtures. A series of these materials based on choline chloride (HOCH2CH2NMe3Cl) and either zinc chloride or urea have been reported (Abbott et al., 2002 2003). The urea/choline chloride material has many of the advantages of more well-known ionic liquids (e.g. low volatility), but can be sourced from renewable feedstocks, is non-toxic and is readily biodegradable. However, it is not an inert solvent and this has been exploited in the functionalisation of the surface of cellulose fibres in cotton wool (Abbott et al, 2006). Undoubtedly, this could be extended to other cellulose-based materials, biopolymers, synthetic polymers and possibly even small molecules. 

Synonyms and trade names cyanoethylene, 2-propenenitrile, vinyl cyanide Use and exposure Acrylonitrile is a colorless, man-made liquid with a sharp, onion- or garlic-like odor. It can be dissolved in water and evaporates quickly. Acrylonitrile is used principally as a monomer in the manufacture of synthetic polymers, polyacrylonitriles, acrylic fibers, and other chemicals such as plastics and synthetic rubber. A mixture of acrylonitrile and carbon tetrachloride was used as a pesticide in the past. - Acrylonitrile is highly flammable and toxic. It undergoes explosive polymerization. The... 

Polymer nanoparticles including nanospheres and nanocapsules (Fig. 1) can be prepared according to numerous methods that have been developed over the last 30 years. The development of these methods occurred in several steps. Historically, the first nanoparticles proposed as carriers for therapeutic applications were made of gelatin and cross-linked albumin. Then, to avoid the use of proteins that may stimulate the immune system and to limit the toxicity of the cross-linking agents, nanoparticles made from synthetic polymers were developed. At first, the nanoparticles were made by emulsion polymerization of acrylamide and by dispersion polymerization of methylmethacry-late.f These nanoparticles were proposed as adjuvants for vaccines. However, since they were made of non-biodegradable polymers, these nanoparticles were rapidly substituted by particles made of biodegradable... 

Several of the most effective polymeric delivery systems were polyamidoamine den-drimers (220) and polyethyleneimines (PEI) (221). Being non-biodegradable, these synthetic polymers posed a potential toxicity to cell therefore, biodegradable polypeptides like PLL and protamine were used for condensation and delivery of gene, but they had limited efficacy in transfection (222, 223). They were usually used with cationic lipids to obtain enhanced transfection activity (178,201). Among the biodegradable polymers, chitosan... 

Evolved gas analysis, particularly in the form of TGA-DTA-MS, has obvious synthetic polymer applications. It has been applied to study the thermal behavior of homopolymers, copolymers, polymeric blends, composites, residual polymers, solvents, additives, and toxic degradation polymers. In the latter context, hydrogen chloride evolution from heated polyvinylchloride materials is readily quantified by TGA-DTA-MS and such data are of major significance in... 

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