Use of Amphoterics

From the 1970s, the introduction of tampon solutions or amphoteric solutions, particularly in France and Germany, was quite difficult because of the legislation, which would not include specific cases. Particularly in France, it was difficult to convince the doctors of the interest of amphoteric solutions, which did not let heat out, but brought the skin or eye to a neutral pH and left no acid or alkali residue. This situation was partly due to a weak knowledge of chemistry in the medical world, whereas it was easier to convince chemists. Anyway, the use of amphoteric solutions has little by little spread into the industrial world and lead to some exciting results, hi opposition to previous reasoning, it was noticed that the... 

One approach which almost certainly deserves further attention is based on the use of amphoteric or ion retardation resins, which have the capacity to remove both positive and negative ions simultaneously from a solution (Figure 1). The resin holds both ions in close proximity, and the positive and negative charges tend to neutralize one another because they occupy adjacent positions on the resin. There is no need to supply energy actually to neutralize the ions. 

Dybczynski, R., Samczynski, Z. The use of amphoteric ion exchange resin for the selective separation of cadmium from other radioelements present in neutron irradiated biological materials. J. Radioanal. Nucl. Chem. 150, 143-153 (1991)... 

Amphoteric surfactants offer an excellent degree of lubrication, corrosion inhibitor, and wetting action and provide a protective colloid for silk and wool processing. The major uses of amphoterics are in the scouring and dyeing of protein fibres to prevent chafing, crack marks and crow s feet. Amphoterics are comparatively expensive and some of them are not heat stable and hence cannot be used at elevated temperature. 

Another interesting aspect is that shower enclosures are usually either ceramic (grouted tiles) or plastic (methacrylate, or Plexiglas ). One patent emphasizes the choice of surfactant and its effect on plastic. Nonionic surfactants have been said to cause crazing in plastic surfaces [300], and one shower rinse formulation claims the use of amphoteric surfactants for superior soil removal and greater safety to plastic surfaces [301],... 

As the line between therapeutic cosmetics (cosmeceuti-cals) and drugs becomes more vague, the use of amphoteric surfactants in the development of products which are evaluated through clinical trials is likely to increase. This is especially true concerning the use of amphoteric surfactants in the oral care industry. 

The most recent patent references to amphoteric surfactants for the pharmaceutical industry involve the development of new diagnostic test methods. These include immunochemical assays and improved genetic diagnostic methods. In these applications, the selective use of amphoteric surfactants has been shown to enhance the sensitivity of detection (117-119). 

The use of amphoteric surfactants in heavy industry is a broad topic encompassing such varied applications as oil well and mining fluids, fire fighting foams, printing inks, wastewater effluent recovery aids, leather softeners, electroplating bath additives and corrosion inhibitors (120-129). While these topics are beyond the scope of this present chapter, they are worth mentioning since developments involving amphoteric surfactants here will ultimately have an impact on their consumption and availability in consumer markets and elsewhere. 

Goldich Y, Barkana Y, Zadok D et al (2013) Use of amphoteric rinsing solution for the treatment of ocular tissues exposed to nitrogen mustard. Acta Ophthalmol 91 e35-e40... 

Significant changes in the activity and the selectivity in this system can be made by varying the nature of the support. The use of amphoteric oxide supports such as Zr02 and Ti02 catalyzed the selective formation of methyl formate, whereas the use of non-... 

Amphoteric polysaccharides are those polyglycans capable of carrying both cationic and anionic charges on the same chain. The term amphoteric derives from the Greek am-photeros, which means both. There are very few naturally occurring amphoteric polysaccharides most of those used cosmetically are seminatural derivatives. Amphoteric polysaccharides are relatively unknown and underutilized in cosmetics although the use of amphoteric surfactants in personal care is quite common. 

Amphoteric surfactants are characterized by the fact that these surfactants can carry a positive charge on a cationic site and a negative charge on an anionic site. The use of amphoteric terminology is still restrictive The charge of the molecule must change with pH, showing a zwitterionic form at an intermediate pH (i.e., around the isoelectric point). 

In a notable exception, Yudin has described the use of amphoteric aldehydes (178) in an Ugi MCR with isonitriles and linear peptides (179) to prepare a series of modified peptidomimetie macrocycles (180) with ring sizes from 9 to 18 atoms (Scheme 11.24). These compounds, via nucleophilic attack on the aziridine, also can be employed as intermediates for further reactions and, hence, provide access to additional structural diversity suitable for library production. Towards this end, the sequence was successfully transferred to an automated mierofluidies platform. The process did not need to be performed under high dilution eonditions (0.2 M). More recently, this approach was applied sueeessfully to the synthesis of bityclic peptidomimetie derivatives, for example 181, in whieh macrocyclization and then disulfide formation were best eondueted in solution after the solid phase MCR to avoid side reaetions. ... 

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