Toxicity nonionic surfactants

To overcome these difficulties, drilling fluids are treated with a variety of mud lubricants available from various suppHers. They are mostly general-purpose, low toxicity, nonfluorescent types that are blends of several anionic or nonionic surfactants and products such as glycols and glycerols, fatty acid esters, synthetic hydrocarbons, and vegetable oil derivatives. Extreme pressure lubricants containing sulfurized or sulfonated derivatives of natural fatty acid products or petroleum-base hydrocarbons can be quite toxic to marine life and are rarely used for environmental reasons. Diesel and mineral oils were once used as lubricants at levels of 3 to 10 vol % but this practice has been curtailed significantly for environmental reasons. 

Nonionic surfactants and phenoUc resins based on alkylphenols are mature markets and only moderate growth in these derivatives is expected. Concerns over the biodegradabiUty and toxicity of these alkylphenol derivatives to aquatic species may limit their use in the future. The use of alkylphenols in the production of both polymer additives and monomers for engineering plastics is expected to show above average growth as plastics continue to replace traditional building materials. 

Subacute and chronic toxicity of alcohol and alcohol ether sulfates has been extensively tested in several animals and sometimes humans. The duration of the tests was in some cases as long as 2 years. When administered below the toxic amount no specific damages were observed in any of the species tested [333]. No severe side effects were observed in the study by Swisher, carried out with volunteers who ingested considerable amounts of anionic and nonionic surfactants over long periods [348]. Similarly, the effects produced by the intake of daily doses of 1 g of alcohol sulfate per person over 8 weeks [349],... 

Surfactants. The use of surfactants is greatly restricted in formulating ophthalmic solutions. The order of surfactant toxicity is anionic > cationic >> nonionic. Several nonionic surfactants are used in relatively low concentrations to aid in dispersing steroids in suspensions and to achieve or to improve solution clarity. Those principally used are the sorbitan ether esters of oleic acid (Polysorbate or Tween 20 and 80), polymers of oxyethylated octyl phenol (Tyloxapol), and polyoxyl 40 stearate. The lowest concentration possible is used to perform the desired function. Their effect on preservative efficacy and their possible binding by macromolecules must be taken into account, as well as their effect on ocular irritation. The use of surfactants as cosolvents for an ophthalmic solution of chloramphenicol has been described [271]. This com-... 

NPE was previously used extensively as nonionic surfactants and emulsifiers in both the textile and the leather industry but has now been replaced by alternative surfactants in Europe. The main alternatives in the leather industry are linear alcohol ethoxylates with different chain lengths and ethoxylation degrees. These compounds are much easier than NPE degraded to non-toxic compounds. The efficiency of linear alcohol ethoxylates as degreasing agents is comparable to that of NPE. 

Giger W, Brunner PH, Schaffner C (1984) 4-Nonylphenol in sewage sludge accumulation of toxic metabolites from nonionic surfactants. Science 225 623-625... 

The mitochondrial respiratory parameters have also been employed to determine the toxicity of surfactants, including anionic (LAS), nonionic (NPEO) and their metabolites, sulfophenyl carboxylates (SPCs), NP and nonylphenoxy carboxylate (NPECi) [37]. The system employed was the in vitro response of submitochondrial particles from beef heart. The EC50 toxicity calculated as the reduction rate of NAD+ ranged from 0.61 mg L-1 for a commercial LAS mixture to 18 000 mg L-1 for SPCs, and 1.3 mg L-1, 8.2 and 1.8mgL 1 for NPEOio, NPECi and NP, respectively. These results indicate that from the toxicity perspective, LAS is the compound demanding increased attention, while for NPEO, the parental compound and the metabolites must be quantified. 

Nonionic surfactants of general structure 176, used in off-shore drilling (e.g. Nonidet AT 85), are toxic and slowly biodegradable. They can be determined in an FIA system by... 

Nonionic surfactants contain (Fig. 23) no ionic functionalities, as their name implies, and include ethylene oxide adducts (EOA) of alkylphenols and fatty alcohols. Production of detergent chain-length fatty alcohols from both natural and petrochemical precursors has now increased with the usage of alkylphenol ethoxylates (APEO) for some applications. This is environmentally less acceptable because of the slower rate of biodegradation and concern regarding the toxicity of phenolic residues [342]. 

In some biological systems nonionic surfactants have an intrinsic biological activity the Ci2 alkyl ethers were too toxic to be used in the experiments of drug absorption with goldfish. The activity of the C12 ethers was quantified by measurement of the fish turnover time, T. When the reciprocal of the turnover time is plotted against alkyl chain length for the series Cx and Ejq and C12 compound is distinguished by its marked effect. (12). 

The experimental first-order decay rate for pentachlorobenzene in an aqueous solution containing a nonionic surfactant micelle (Brij 58, a polyoxyethylene cetyl ether) and illuminated by a photoreactor equipped with 253.7-nm monochromatic UV lamp is 1.47 x lO Vsec. The corresponding half-life is 47 sec. Photoproducts reported include all tetra-, tri-, and dichlorobenzenes, chlorobenzene, benzene, phenol, hydrogen, and chloride ions (Chu and Jafvert, 1994). Chemical/Physical. Emits toxic chlorinated acids and phosphene when incinerated (Sittig,... 

Indeed, the selection of raw materials from the pharmaceutical perspective is severely restricted by toxicity concerns, and Attwood and Florence (1998) suggested that only a few nonionic surfactants such as polysorbates 80 and 20 may be suitable for oral administration, with the possibility of some phospholipids serving the same function. Since that time a small number of other nonionic surfactants (e.g., cremo-phores) have been evaluated. 

The micelle formulation approach often possesses disadvantages such as its toxicity associated with surfactants even at relatively low concentrations. In general, nonionic surfactants have the least toxic effects. Cremophor EL produces hypersensitivity reactions in human and animals (Jonkman-de Vries et al., 1996). Tween-80 is also believed to cause acute hepatitis and renal failure (Uchegbu and Florence, 1996). On intravenous administration, owing to their surface activity, surfactant molecules have the potential to penetrate and disrupt biological membranes and can be hemolytic (Ten Tije et al., 2003). Often the absorption capacity of the micelle is too small and the extent of the... 

In contrast to the conventional emulsions or macroemulsions described earlier are the disperse systems currently termeraiicroemulsions. The term was Lrst introduced by Schulman in 1959 to describe a visually transparent or translucent thermodynamically stable system, with much smaller droplet diameter (6-80 nm) than conventional emulsions. In addition to the aqueous phase, oily phase, and surfactant, they have a high proportion of a cosurfactant, such as an alkanol of 4-8 carbons or a nonionic surfactant. Whereas microemulsions have found applications in oral use (as described in the next chapter), parenteral use of microemulsions has been less common owing to toxicity concerns (e.g., hemolysis) arising from the high surfactant and cosolvent levels. In one example, microemulsions composed of PEG/ethanol/water/medium-chain triglycerides/Solutol HS15/soy phosphatidylcholine have been safely infused into rats at up to 0.5 mL/kg. On dilution into water, the microemulsion forms a o/w emulsion of 60-190 nm droplet size (Man Corswant et al., 1998). 

Emulsions are two-phase systems formed from oil and water by the dispersion of one liquid (the internal phase) into the other (the external phase) and stabilized by at least one surfactant. Microemulsion, contrary to submicron emulsion (SME) or nanoemulsion, is a term used for a thermodynamically stable system characterized by a droplet size in the low nanorange (generally less than 30 nm). Microemulsions are also two-phase systems prepared from water, oil, and surfactant, but a cosurfactant is usually needed. These systems are prepared by a spontaneous process of self-emulsification with no input of external energy. Microemulsions are better described by the bicontinuous model consisting of a system in which water and oil are separated by an interfacial layer with significantly increased interface area. Consequently, more surfactant is needed for the preparation of microemulsion (around 10% compared with 0.1% for emulsions). Therefore, the nonionic-surfactants are preferred over the more toxic ionic surfactants. Cosurfactants in microemulsions are required to achieve very low interfacial tensions that allow self-emulsification and thermodynamic stability. Moreover, cosurfactants are essential for lowering the rigidity and the viscosity of the interfacial film and are responsible for the optical transparency of microemulsions [136]. 

Table IX Toxicity to Fish after 5d Biodegradation for Nonionic Surfactant (14)...

Nonionic surfactants consist of a -(CH2CH20)n0H or -OH as the hydrophilic group and exhibit a variety of hydrophile-lipophile balances (HLB) which stabilize O/W or W/O emulsions. Unlike anionic and cationic surfactants, nonionic surfactants are useful for oral and parenteral formulations because of their low irritation and toxicity. Based on their neutral nature, they are much less sensitive to changes in the pH of the medium and the presence of electrolytes. The best use of nonionic surfactants is to produce an equally balanced HLB of two nonionic surfactants one... 

Structure-activity relationships between several nonionic surfactants and three water-soluble herbicides have been studied (58). In general it has been shown that the herbicide, the surfactant concentration, the hydrophilic constitution (ethylene oxide content), and the hydrophobic portion of the molecule all markedly influence toxicity. 

Schomacker compared the use of nonionic microemulsions with phase transfer catalysis for several different types of organic reactions and concluded that the former was more laborious since the pseudo-ternary phase diagram of the system had to be determined and the reaction temperature needed to be carefully monitored [13,29]. The main advantage of the microemulsion route for industrial use is related to the ecotoxicity of the effluent. Whereas nonionic surfactants are considered relatively harmless, quaternary ammonium compounds exhibit considerable fish toxicity. 

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