Amphoteric bodies

Winterl s theoretical views were summarised in 1800-3. He recognised that acids need not contain oxygen, that silica has acidic properties (overlooked by his contemporaries, but known to Tachenius, etc., see Vol. II), and that many metallic calces are acidic. He used the name amphoteric bodies ... 

Over the years, optimized amphoacetates were developed that were intermediate between the 1 and 2-mol products. An effort was made to deliver more amphoteric surfactant and less by-products to the formulator. Most baby shampoos and body washes produced today are formulated with such optimized products, which are produced from an optimum ratio... 

We call compounds, like amino acids, that can act as acids or bases depending on their environment amphoteric compounds. The body uses this dual property in the stomach, as the protein stomach juices and lining can react to mop up any adverse effects of overeating or drinking (within reason). If the system is overloaded you might have to help a bit by taking a Rennie or stomach powder to help restore the correct acidity to the stomach. 

Cocaine metabolizes in the body to several compounds. The NIDA drug confirmation is based on the metabolite, benzoylecgonine. Benzoylecgonine is an amphoteric compound (contains both an amine and a carboxylic acid) that will isolate by mixed-mode SPE (Fig. 8.6). 

Ci7H35CONHCH2CH2CH2"N(CH3)2CH2COO-Properties M.w. 426.68 amphoteric Uses Surfactant, conditioner, detergent, thickener, foam builder for shampoos and emollient body treatments textile softener, antistat... 

The major applications of this class of surfactants are shampoos and body washes, and they are often found in conditioning shampoos due to their compatibility with quaternary compounds. The shampoo compositions mostly include from 1 to —8% by weight of amphoterics to help impart aesthetic, physical, or cleansing properties to the composition. Amphoterics also find broad applications in hard surface cleaner formulations and homecare applications, due to their excellent detergency and pH stability. 

Chapter 8 is a review of the use of polysaccharides, perhaps some of the oldest and most well-known ingredients used in personal care. Because polysaccharides are derived from natural sources, the nature of the monosaccharides that comprise these sugar-based polymers and how nature designs the polysaccharides are addressed first. This discussion is followed by greater details of individual cosmetically important polysaccharides based primarily on the ionic nature of the polysaccharide, that is, anionic, cationic, nonionic, or amphoteric, which can be either naturally developed by the polysaccharide source or manipulated by human intervention and invention. The effects of hydrophobic modification of polysaccharides are also discussed. The chapter concludes with a brief discussion of certain polysaccharides that appear to have physiological effects on the human body when applied topically. 

Oxides that can exhibit bodi addic and basic characters are said to be amphoteric. (Section 163) If a metal forms more than one oxide, die basic character of die oxide decreases as die oxidation state of the metal increases. 

These are the structural units of protein. The term amino indicates the presence of the NHj group-a base-while the term acid indicates the presence of the COOH groups or carboxyl group-an acid. Since all amino acids possess this unique chemical feature of containing both an acid and a base, they are capable of both acid and base reactions in the body. Thus, they are said to be amphoteric. There are 22 amino acids. 

In the search for unknown drugs and/or pharmaceuticals in body fluids, a combined instrumental approach is especially helpful. Table III shows our extraction scheme. For drug analysis, steam distillation is usually omitted. Different extraction steps isolate the strongly acidic, weakly acidic, neutral, basic and amphoteric compounds in separate fractions. All are analyzed by UV-spectro-photometry, in organic solution and (with the exception of the neutral extract) also in water at 3 different pH-values. Thin- layer chromatography, color tests, IR- and fluorescence-spectrophotometry may yield additional information. Fractions of interest are analyzed by GC-MS. 

Amino acids are amphoteric - they show both acidic and basic properties, depending on conditions. The pH of many body tissues is near pH 7. At this pH both the NH and the COOH groups of the amino acid are ionised. So at pH 7 an amino acid, e.g. glycine, exists in a charged form in which the + and - charges are balanced ... 

Chem. Descrip. Cocoamphopolycarboxyglycinate Ionic Nature Amphoteric CAS 97659-53-5 EINECS/ELINCS 307-458-3 Uses Substantive cosmetic ingred., foaming agent, biostat for shampoos, liq. soaps, body care prods. 

Uses Emulsifer, stabilizer, pearlizer, opacifier for hand dishwashing detergents, rinses, cosmetics, liquid hand soaps, body cleaners, and shampoos Features Compat. with cationic, amphoteric, anionic and nonionio surfactants Properties Wh. flake HLB 1 acid no. 6 max. sapon. no 190-200 100% solids Canocol EGDS-35 [Centro China]... 

Chem. Descrip. Sodium lauroamphoacetate Uses Surfactant for personal care, shampoos, bubble bath, bath gels, body washes foaming agent, vise, builder far anionic/amphoteric formulations Features Extremely mild... 

Konig and Waldorf discuss analysis of hair and body shampoos (32). The shampoo is first evaporated to dryness and extracted with isopropanol or 95% ethanol to separate the surfactant, which is qualitatively identified by IR. The alcohol-insoluble residue is also examined by IR in case a less-soluble surfactant remains there. The alcohol extract is then separated into anionic, cationic, nonionic, and amphoteric surfactant fractions by ion exchange. Anionics can be separated into sulfonates and carboxylates by use of strongly basic anion exchange resins in the Cl" and OH" form, respectively. Anionics are further characterized by TLC. Nonionics are likewise characterized by TLC. Once the components are identified, quantitative analysis is by the usual methods, described elsewhere in this volume. 

As mentioned above, the increased importance of the imidazoline-derived surfactants stems primarily from their mildness and low toxicity. The extent of their use in shampoos and body care products has followed closely the overall increase in the use of such products worldwide. Their amphoteric nature also makes them useful in a wide range of water types, ranging from hard to soft water and high to low pH. Such flexibility makes them useful in cleaning formulations that will see a variety of conditions. 

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