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Skin lipids

If compression is requited to provide a stick or pan-type of product, the bulk components must be held together with a binder. Common binders ate various Hpids, polymers, polysaccharides, and waxes. Some binder compositions include water, which is removed by drying the compact. The amount of binder must be carefully controlled to yield a soHd, nonfragile compact that is soft enough to pay off. Excessive amounts of or improperly compounded binders glaze during use because of transfer of skin lipids to the compact. [Pg.295]

Chloroform-methanol extracts of Borrelia burgdorferi were used for the identification of lipids and other related components that could help in the diagnosis of Lyme disease [58]. The provitamin D fraction of skin lipids of rats was purified by PTLC and further analyzed by UV, HPLC, GLC, and GC-MS. MS results indicated that this fraction contained a small amount of cholesterol, lathosterol, and two other unknown sterols in addition to 7-dehydrocholesterol [12]. Two fluorescent lipids extracted from bovine brain white matter were isolated by two-step PTLC using silica gel G plates [59]. PTLC has been used for the separation of sterols, free fatty acids, triacylglycerols, and sterol esters in lipids extracted from the pathogenic fungus Fusarium culmorum [60]. [Pg.318]

Using PTLC six major fractions of lipids (phospholipids, free sterols, free fatty acids, triacylglycerols, methyl esters, and sterol esters) were separated from the skin lipids of chicken to smdy the penetration responses of Schistosoma cercaria and Austrobilharzia variglandis [79a]. To determine the structure of nontoxic lipids in lipopolysaccharides of Salmonella typhimurium, monophosphoryl lipids were separated from these lipids using PTLC. The separated fractions were used in FAB-MS to determine [3-hydroxymyristic acid, lauric acid, and 3-hydroxymyristic acids [79b]. [Pg.320]

The majority of RDC studies have concentrated on the measurement of solute transfer resistances, in particular, focusing on their relevance as model systems for drug transfer across skin [14,39-41]. In these studies, isopropyl myristate is commonly used as a solvent, since it is considered to serve as a model compound for skin lipids. However, it has since been reported that the true interfacial kinetics cannot be resolved with the RDC due to the severe mass transport limitations inherent in the technique [15]. The RDC has also been used to study more complicated interfacial processes such as kinetics in a microemulsion system [42], where one of the compartments contains an emulsion. [Pg.340]

Interaction of the liposomal lipids with cellular lipid bilayers or other lipid bilayers in the body (e.g. skin lipids) depends on the nature of the lipids in the liposome. In order to... [Pg.826]

Location of conspecifics in the presence of sympatrics, whether closely related or not, is another skin-lipid based response. Western ribbon snakes (Thamnophis proximus) could not locate own-species scent without VNO access sympatric scents were not recognised (Graves, 1991). [Pg.171]

MONKEY, Macaca fascicularis 1 or 10 mg/kg BW of trans-chlordane given once weekly for 5 weeks by subcutaneous injection. Adipose tissue, blood, and skin lipids analyzed for up to 20 weeks after the last injection trans-Chlordane and oxychlordane were detected in all tissues. In blood and adipose tissue, trans-chlordane decreased rapidly and oxychlordane increased gradually until a plateau was reached. Good correlations were determined for all chemicals between blood and adipose tissue, regardless of collection time and dose level, and between skin lipids and adipose tissue. At the high dose, trans-chlordane reached a maximum of 35 mg/kg FW in adipose tissue, but was not detectable after 20 weeks. The oxychlordane concentration in adipose tissue of the high-dose group was 25 mg/kg FW after the last injection, and 18 mg/kg FW after 20 weeks (Sasaki et al. 1992)... [Pg.870]

Following their use in the behavioral trials, sub-sets of the experimental females (n = 8) and experimental newly-emerged males (n = 8) were immediately sacrificed with an overdose of brevital sodium and their skin lipids were extracted with hexane overnight (LeMaster and Mason 2002). After removal of the animals, the extracts were returned to Western Oregon University where the methyl ketones composing the female sexual attractiveness pheromone were isolated using column chromatography (described in LeMaster and Mason 2002). [Pg.225]

If possible, avoid handling the ceramic shard (and especially the area to be sampled). Wear nitrile gloves or use tweezers. Washing hands before sampling will also reduce the potential of contamination by skin lipids. [Pg.339]

By contrast, Vaseline and similar highly viscous, lipid bases from the outset form an impenetrable layer, virtually unaffected by external factors or effects emanating from the skin itself. Interactions with the skin lipids are only likely at the boundary between ointment and skin. [Pg.476]

Most of the research on human exocrine secretions and excretions has probably been devoted to the chemistry of human skin lipids. To a certain extent, this could be due to the interest of the cosmetic industry in the chemical compounds found on the human skin and the chemical processes they are subjected to by the environment. It is possible that some of the proprietary in-... [Pg.282]

M. W. De Jager, G. S. Gooris, I. P. Dolbnya, W. Bras, M. Ponec, and J. A. Bouwstra. The phase behaviour of skin lipid mixtures based on synthetic ceramides. Chem. Phys. Lipids 124 123-134 (2003). [Pg.30]

A further possibility is the formation of liquid crystals on contact with body fluids at the site of application. The initially applied drug solution interacts with body fluids such as plasma, tears, or skin lipids and undergoes a phase transition into a mono-or multiphasic system of liquid crystals (Fig. 15). For example, oily solutions of reverse micellar solutions of phospholipids, which solubilize additional drug, trans-... [Pg.143]

Male red-sided garter snakes court larger females more than small ones. Even the skin lipid extracts from large females elicit courtship from more males than those from small females. Larger females possess more unsaturated methyl ketones, while small females have more saturated methyl ketones (LeMaster and Mason, 2002). [Pg.179]

Kaplun-Frischoff Y, Touitou E. Testosterone skin permeation enhancement by menthol through formation of eutectic with drug and interaction with skin lipids. J Pharm Sci 1997 86 1394-1399. [Pg.267]

Most animal steroids arise from cholesterol, which in turn is derived from squalene. This C30 triterpene, whose biosynthesis is described in Section B, is named after the dogfish Squalus in whose liver it accumulates as a result of blockage in oxidation to cholesterol. Squalene is also a prominent constituent of human skin lipids. Its conversion to cholesterol, which takes place in most animal tissues,117/154-156 is initiated by a microsomal enzyme system that utilized 02 and NAD-PH to form squalene 2,3-oxide (Fig. 22-6, step a). [Pg.1244]

Ke, P.J., Nash. D.M., and Ackman, R.G. 1977. Mackerel skin lipids as an unsaturated fat model system for the determination of antioxidative potency of TBHQ and other antioxidant compounds. J. Am. Oil Chem. Soc. 54 417-420. [Pg.563]

McIntosh, T.J., M.E. Stewart, and D.T. Downing. 1996. X-ray diffraction analysis of isolated skin lipids Reconstitution of intercellular lipid domains. Biochemistry 35 3649. [Pg.231]

In an interesting work in Farah, Mathura District, India, Dua et al. (1998) collected the skin lipids from face and blood from the occupationally exposed and unexposed volunteers and found that the levels of both HCHs and DDTs were higher in the samples obtained from the exposed group. They have also found an increase in the levels of both the compounds in Delhi population when compared with the data reported in previous publications on the concentrations in the adipose tissue collected a decade before in Delhi (Ramachandran et al., 1984) and several other parts of India (Kaphalia and Seth, 1983), reflecting the intensive use of these pesticides for malaria control in the sampling area. [Pg.465]

Dua, V.K., pant, C.S., Sharma, V.P., Pathak, G.K., 1998. HCH and DDT in surface extractable skin lipid as a neasure of human exposure in India. Bull. Environ. Contain. Toxicol. 60, 238-244. [Pg.478]

Figure 7 The possible mechanisms involved in the effect of penetration enhancers on the lipid organization of the intercellular domains in the stratum corneum. (A) Intercalation of the enhancer in the lipid lamellae. (B) Phase separation between enhancer and skin lipids in the lamellae. (C) Phase separation between lipid lamellae and an enhancer-rich phase. (D) Intercalation of the enhancer in the lipid lamellae and simultaneous phase separation between lipid lamellae and enhancer. (E) Phase separation within the lamellae and separation between an enahncer-rich phase and the lamellar phase. (F) Disappearance of the lamellar phases. Figure 7 The possible mechanisms involved in the effect of penetration enhancers on the lipid organization of the intercellular domains in the stratum corneum. (A) Intercalation of the enhancer in the lipid lamellae. (B) Phase separation between enhancer and skin lipids in the lamellae. (C) Phase separation between lipid lamellae and an enhancer-rich phase. (D) Intercalation of the enhancer in the lipid lamellae and simultaneous phase separation between lipid lamellae and enhancer. (E) Phase separation within the lamellae and separation between an enahncer-rich phase and the lamellar phase. (F) Disappearance of the lamellar phases.
M. Fresta and G. Puglisi, Corticosteroid dermal delivery with skin-lipid liposomes. J. Contr. Rel. 44 141-151 (1997). [Pg.163]

Irritant dermatitis does not involve an immune response and is typically caused by contact with corrosive substances that exhibit extremes of pH, oxidizing capability, dehydrating action, or tendency to dissolve skin lipids. In extreme cases of exposure, skin cells are destroyed and a permanent scar results. This condition is known as a chemical burn. Exposure to concentrated sulfuric acid, which exhibits extreme acidity, or to concentrated nitric acid, which denatures skin protein, can cause bad chemical bums. The strong oxidant action of 30% hydrogen peroxide likewise causes a chemical bum. Other chemicals causing chemical bums include ammonia, quicklime (CaO), chlorine, ethylene oxide, hydrogen halides, methyl bromide, nitrogen oxides, elemental white phosporous, phenol, alkali metal hydroxides (NaOH, KOH), and toluene diisocyanate. [Pg.204]


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See also in sourсe #XX -- [ Pg.64 , Pg.66 ]

See also in sourсe #XX -- [ Pg.25 , Pg.176 , Pg.190 ]

See also in sourсe #XX -- [ Pg.27 , Pg.113 , Pg.114 , Pg.159 , Pg.178 , Pg.286 , Pg.349 , Pg.376 ]




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