Toxicity acrylamide monomer

The reaction with sodium sulfite or bisulfite (5,11) to yield sodium-P-sulfopropionamide [19298-89-6] (C3H7N04S-Na) is very useful since it can be used as a scavenger for acrylamide monomer. The reaction proceeds very rapidly even at room temperature, and the product has low toxicity. Reactions with phosphines and phosphine oxides have been studied (12), and the products are potentially useful because of thek fire retardant properties. Reactions with sulfide and dithiocarbamates proceed readily but have no appHcations (5). However, the reaction with mercaptide ions has been used for analytical purposes (13)). Water reacts with the amide group (5) to form hydrolysis products, and other hydroxy compounds, such as alcohols and phenols, react readily to form ether compounds. Primary aUphatic alcohols are the most reactive and the reactions are compHcated by partial hydrolysis of the amide groups by any water present. 

Contact with acrylamide can be hazardous and should be avoided. The most serious toxicological effect of exposure to acrylamide monomer is as a neurotoxin. In contrast, polymers of acrylamide exhibit very low toxicity. 

Acrylamide monomer, which is frequently used as a grouting material to prevent the infiltration of ground water into sewer lines, is toxic to the body s nervous system. At least 56 reported cases of poisoning have occurred in workers exposed to acrylamide. Thirteen of these cases occurred in individuals using acrylamide for waterproofing and soil stabilization at a construction site. 

Poly(N-isopropyl acrylamide) (PNIPAAm) is one of the most widely studied temperature sensitive polymers that undergoes clear solution to precipitation. However, its nonbiodegradabihty and concern for residual monomer toxicity limit the biomedical applications. To improve the problems, biodegradable... 

The residual monomer left in polyacrylamides is toxic, but may be reduced to an acceptable level by firrther processing. Special grades have been available espedalfy for potable water treatment which are guaranteed to contain less than 0.025% of fi ee acrylamide monomer and the use of these grades is likely to extend into enviromnentaUy sensitive applicafibns. 

There is a demand for non-toxic flocculants for use in potable water treatment and similar applications. The toxic component of polymers is the residual acrylamide monomer content. To enable a formal classification of low toxicity, the acrylamide content must be 0.025% or less for use in most European countries (0.05% in the USA). Some standard polymers meet this requirement, but extra work, and thus extra cost, is required to provide the certification and enforce the quality control. 

Due to its toxicity, very sensitive methods are required to determine acrylamide monomer in polyacrylamide. 

Only relatively recently has it been discovered that acrylamide, and possibly also the substituted acrylamides, are toxic in a unique manner. Neuromuscular disorders of varying severity have been reported. The monomer may be absorbed through the intact skin, by inhalation, or by ingestion. There may be a degree of cumulative toxicity in animals. It is suggested that reference [24] be consulted for recommendation of safety precautions that should be taken when handling acrylamide and related compounds. 

The main disadvantage in using poly(acrylamide) systems is that they are not biodegradable and the monomers are toxic. Extensive purification is also required to remove the organic solvents, anionic surfactants, and residual monomers. Edman et al. [74] produced biodegradable poly(acryldextran) particles by incorporating dextran into the poly(acrylamide) chain. These particulate systems were metabolized and eliminated faster, both in vivo and in vitro, than poly(acrylamide) particles. 

Caution Acrylamide is very toxic. Avoid inhalation of dust and wear gloves during manipulation with monomers ... 

More than a dozen biocompatible and biodegradable polymers have been described and studied for their potential use as carriers for therapeutic proteins (Table 13.5). However, some of the monomer building blocks such as acrylamide and its derivatives are neurotoxic. Incomplete polymerization or breakdown of the polymer may result in toxic monomer. Among the biopolymers, poly-lactide cofabricated with glycolide (PLG) is one of the most well studied and has been demonstrated to be both biocompatible and biodegradable [12]. PLG polymers are hydrolyzed in vivo and revert to the monomeric forms of glycolic and lactic acids, which are intermediates in the citric acid metabolic pathway. 

Based on animal studies and mutagenicity studies, trace amounts of organic polymers do not appear to present a toxicity problem in drinking water. The reaction products with both chlorine and ozone also appear to have low toxicity. The principal concern is the presence of unreuctcd monomer and other toxic and potentially carcinogenic nonpolymeric organic compounds in commercial polymeric flocculants. The principal contpuimds are acrylamide in acrylamide based polymers, dimethyldiallyammonium chloride in allylie polymers, and epichlorohydrin and chlorinated propanols in polyamines, as well as the rcaclion products of these compounds with ozone and chlorine. 

Shea and colleagues [109-111] added an exciting contribution to this field They created molecular imprints for the peptide melittin, the main component of bee venom, in polymer nanoparticles, resulting in artificial antibody mimics that can be used for the in vivo capture and neutralization of melittin. Melittin is a peptide comprising 26 amino acids which is toxic because of its cytolytic activity. Shea and colleagues strategy was to synthesize cross-linked, acrylamide-based MIP nanoparticles by a process based on precipitation polymerization using a small amount of surfactant. To maximize the specificity and the affinity for melittin, a number of hydrophilic monomers were screened for complementarity with the template. The imprinted nanoparticles were able to bind selectively the peptide with an apparent dissociation constant of Ax>app > 1 nM [109]. 

Clinical applications of thermosensitive hydrogels based on NIPAAm and its derivatives have limitations [121], The monomers and cross-linkers used in the synthesis of the hydrogels are still not known to be biocompatible and biodegradable. The observation that acrylamide-based polymers activate platelets upon contact with blood, together with the unclear metabolism of poly(NIPAAm), requires extensive toxicity studies before clinical applications can merge. 

Monomers, plastics adhesives and resins are consequences of the production and use of polymers. They have a strong environmental impact in waters and soils due to their low biodegradability. It is very common to find plastic residues in marine sediments, soils, seashores, lakes, and rivers. Furthermore, some of the monomers used in their production are volatile and toxic (e.g., acrylamide, isocyanates, and vinyl chloride). 

Polymeric chemicals are a somewhat special case. These are most frequently introduced as direct additives as coagulant aids. By virtue of their function, these polymers are almost quantitatively removed from the water during normal treatment. Even if applied inappropriately, these chemicals are of such high molecular weight that they would not be absorbed and are almost certainly not a threat to health if they have been properly tested. A potential difficulty with these chemicals is that they may contain varying amounts of the monomers used in their synthesis or other incompletely reacted material of lower molecular weight. Some of the monomeric compounds are quite toxic. Acrylamide is an example of one of these compounds that is neurotoxic. 

Disadvantages include the slow removal of the staining dyes and the toxicity of the monomer. It is recommended that prepared gels be purchased if possible to minimize the toxicity problem. Acrylamide has a neurotoxic effect by inhalation and skin contact. Wash any exposed area with soap and water immediately. The effects are drowsiness, fatigue, tingling in the extremities, and weakness in the legs. See Appendix A, Experiment No. 41 for the preparation techniques. 

Safety concerns for synthetic polymers are sometimes due to contamination with monomeric impurity. Monomers are sometimes highly toxic (e.g., acrylamide [94]) or even carcinogenic (e.g., ethyleneimine [95] or vinyl chloride [96]) or highly irritating to skin (e.g., acrylamide [94] or acrylic acid [97]).Therefore, control of unreacted monomer level can sometimes be critical to the safety performance of synthetic polymers. 

Health risks (excluded the use of common chemicals for chromatography) Not significative Grinding produces submicrometric particles, dangerous if inhaled. Some monomers (acrylamide, styrene) are toxic... 

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