Surfactants cholic acid

Fig. 12 Structure for the nonclassical surfactants cholic acid and generic structural features for polysorbates and...

Although similar efforts have been devoted to related polymer systems (Overberger and Cho, 1968 Overberger and Dixon, 1977 Okamoto, 1978), large enantioselectivity has not been observed. Goldberg et al. (1978) conducted borohydride reduction of phenyl ketones in micelles of the chiral surfactant [44]. The result was disappointing, since the maximal enantioselectivity was only 1.66% for phenyl propyl ketone. A much better optical yield was reported when this reaction was carried out under phase-transfer conditions (Masse and Parayre, 1976). The cholic acid micelle and bovine serum albumin exhibited the relatively high enantioselectivity in the reduction of trifluoroacetophenone (Baba ef al., 1978). 

Salts of cholic acid and its derivatives are known as bile salts. Bile salts are unlike traditional surfactants in that they are rigid and have multiple polar moieties on one side of the molecule thus exhibiting surface activity. 

Artificial analogues of the chloride transporter prodigiosin are effective symport HC1 carriers as exemplified in the model systems developed by the groups of Gale [39] and Davis [40], Biological inspiration is also behind another Cl- carrier. Cholic acid is a naturally occurring bile acid that functions as a surfactant in the intestine. Derivatives with three binding sites known as cholapods are able to transport isolated anions across lipid bilayers [41],... 

Channel walls are assumed to be biocompatible, but so is the carrier phase, which can be added with specific surfactants to avoid aggregation during separations so far, bovine serum albumin (BSA) " (and, recently, cholic acid) appeared to be more stable and at least as efficient. Such precautions must be associated with systematic recovery measurements—a multidimensional concept associated with the detector pattern, and a comparison of the cmde sample with every collected fraction. 

Naturally occurring surfactants are represented by various biologically active substances, among which lipids, proteins, and cholic acids are of particular significance for the life cycle of living organisms. 

Taking into account the unsurpassed mildness of all these surfactants, promising sphere of their application is "no-more-tears" child shampoos and products for intimate hygiene. In various combinations phosphobetaines and phosphatobetaines are patented in a range of personal care products by Johnson Johnson [44, 45, 111]. Zwitter-ionic 3-amidopropyldimethylammonio-l-propane-3-sulphonate derived from cholic acid (ChAPS) has been used as selective membrane protein solubiliser in the biochemical practice. All surface-active betaines are compared favourably with quaternary ammonium compounds in respect to their moderate toxicity, low mucous membrane irritation and better biodegradation. 

Photon Correlation Spectroscopy Diameters of Dynasan 114, 116, and 118 Solid Lipid Nanoparticles Stabilized with Mixtures of Cholic Acid Sodium Salt (NaCh) and poloxamer 407 (5% Lipid, 0.5% Surfactant) to Assess the Influence of Different Surfactant Mixtures on the Enzymatic Degradation (Lipase/Colipase Assay) of Solid Lipid Nanoparticles... 

Extending the scope of combined chiral selector systems beyond CDs, one may note that this mode has been used in CE for a rather long time [53-56], The very first example of combined chiral selectors in CE seems to be the report by Fanali et al. [53] in 1989 when 15 mM L-(+)-tartaric acid buffer was used in combination with 15 mM P-CD in order to resolve the enantiomers of chiral cobalt complexes. CDs have also been combined with chiral surfactants such as cholic acids [54, 55] and synthetic micelle-forming agents [56], In recent years, several studies were published on the combination of CDs with chiral [57, 58] and achiral [51, 59-61] crown ethers. The latter studies [59-62] where the achiral crown ether cannot contribute to enantioseparations independently clearly illustrate that the simplified approach described in [12, 47] may not be universally applied to all dual chiral separation systems in CE. 

Certain steroid bile acids such as cholic acid (Section 4-7) also have surfactant or detergent-like properties and are found in the bile duct. These substances are released into the upper intestinal tract, where they emulsify water-insoluble fats through the formation of micelles. Hydrolytic enzymes can then digest the dispersed fat molecules. 

Naturally occurring micellar systems, such as phospholipids and bile salts (e.g. cholic and desoxycholic acids, as well as surfactants affect the rates of numerous chemical reactions in vivo and in vitro (Hanahan, 1960 Kavanau, 1965 Knaak et al., 1966a, b Elworthy et al., 1968 Marriott, 1969). The effects of micellization on enzymatic reactions and other biochemical processes have been discussed by Elworthy et al. (1968), Jencks (1969), and Mysels (1969). 

Neutral steroidal glucoside surfactants, such as N,N-bis-(3-D-gluconamidopropyl)-cholamide (Big CHAP) and A,A-bis-(3-D-gluconamidopropyl)-deoxychola-mide (Deoxy Big CHAP), which contain a cholic or deoxycholic acid moiety, respectively, have been introduced for use as chiral pseudo-stationary phases in MEKC. By using a borate buffer under basic conditions, these surfactant micelles could be charged via borate complexation. Some binaphthyl enantiomers, Troger s base, phenoxy acid herbicide, and Dns-DL-AAs were enantioseparated. 

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