Surfactant acyl lipids

Fig. 6.4 shows the IT-A curves obtained for microbubble-surfactant monolayers on a variety of aqueous subphases. In order to compare Il-A measurements for monolayers which would contain essentially only glycopeptide-acyl lipid complexes, the data plotted in Fig. 6.4 include only Il-A measurements made during the expansion phase (following an initial compression to at least 23 dyne/cm). Judging from the fact that subphases of either distilled water, 0.1 M HC1 (pH 1.1), 0.1 M NaOH (pH 12.3), or 0.1 M NaF... 

Interestingly, the FIA-FI plots for microbubble-surfactant monolayers on subphases other than distilled water provide indirect evidence for induced association of the glycopeptide-acyl lipid complexes themselves. It can be seen from Fig. 6.5 that the monolayer data obtained on subphases of 0.1 M NaF, 0.1 M HC1,... 

Fig. 7.1 shows a typical H-NMR spectrum obtained with the partially purified, microbubble surfactant mixture prior to monolayer formation. For comparison, Table 7.1 gives the chemical-shift data for the proton resonances that can be readily identified in the 1 H-NMR spectra of long-chain acyl lipids (ref. 395-401). 

Vineland, NJ) or over-the-counter cosmetic creams promoted for improved hydration (L Oreal, Paris and Dior, Paris). More recently, parenteral liposome formulations of amphotericin B, doxorubicin, and dau-norubicin have been approved and marketed (ABELCET, Elan, the Liposome Co., Inc, Princeton, NJ AmBisome and DaunoXome, Nexstar/Fujisawa, Deerfield Park, IL Amphotec and Doxil, Sequus/ Alza, Menlo Park, CA), with others on the horizon for applications in photodynamic therapy. Although the vast majority of liposome preparations are constructed from phospholipids, other nonphospholipid materials can be used either alone or in mixtures to form bilayer arrays. One such example is Amphotec, which utilizes sodium cholesteryl sulfate as the primary lipid. Other liposome forming materials may include but are not limited to fatty-acid compositions, ionized fatty acids, or fatty acyl amino acids, longchain fatty alcohols plus surfactants, ionized lysophospholipids or combinations, non-ionic or ionic surfactants and amphiphiles, alkyl maltosides, a-tocopherol esters, cholesterol esters, polyoxyethylene alkyl ethers, sorbitan alkyl esters, and polymerized phospholipid compositions. ° ... 

Pulmonary surfactant protein C (SP-C) is a small hydrophobic peptide. The effect of acylation of SP-C on its structure and function was reported by Haagsman et al. [146] using the Whilelmy plate method and CD spectra measurement. Also, SP-C-induced bilayer interaction was studied via the lipid mixing method by the use of fluorescence spectra of pyrene-PC labeled vesi-... 

The complex morphology of hair essentially consists of four components of different functionality (i) The cortex that gives the hair its mechanical properties consists of elongated, spin-shaped cells aligned in the direction of the fiber axis. The keratinized protein in the form of microfibrils resides in these cells, (ii) The medulla is located in the center of some thicker fibers and it consists of a loosely packed porous cellular structure (it does not contribute to the mechanical properties of the hair), (iii) Cell membrane complex which cements the various cells of the cuticula and the cortex and it consists of several layers, (iv) Cuticle, a multilayered structure which consists of flat cuticle cells and the most outer layer, i.e. the epicuticle (which is about 2.5 nm thick) is the most important part for deposition of surfactants and polymers in the shampoo formulation. This consists of 25 % lipids and 75 % protein, the latter having an ordered possibly p-pleated sheet structure with 12% cystine. The cystine groups are acylated by fatty acids which form the hydrophobic surface region. A schematic representation of the epicuticle is shown in Fig. 1.46. 

The rich lyotropic phase behavior exhibited by membrane lipids is well known. The lyotropic phase behavior of membrane lipids whose structure can be described as diacylglucosylglycerols can be classified as sugar fatty acid esters, and have been studied by Mannock et al. [111]. These types of surfactants often exhibit lamellar phases at low temperature, and a transition to a different inverted nonlamellar mesophase, often reverse hexagonal (Hn) or reverse micellar cubic (Qn) phase. In this particular study acyl chains with different terminus, based on stearic and palmitic acid, were studied. Only the shorter chained derivatives tended to form a Qn phase the remainder formed Hn phases over a range of temperatures above 70 °C. 

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