Lipid classification

Complex lipid classification scheme. Source-. After Lehninger, A. L, et al. (1993). Principles of Biochemistry, 2nd ed., W. H. Freeman, FA = fatty acid Glu = glucose Gal = galactose ROH = alcohol. 

Extracted lipids in this procedure may be used for certain further analysis, such as determination of fatty acid profile f UN1TD1.2) and oxidative state f UNITS 1)2.t 1)2.2) of the oil however, for lipid classification, incomplete extraction of polar lipids into nonpolar solvents may not allow for accurate determination and quantitation. 

Normal-phase sorbents such as silica and Florisil are used to isolate low to moderate polarity species from nonaqueous solutions. Examples of applications include lipid classification, plant pigment separations, and separations of fat-soluble vitamins from lipid extracts, as well as the clean-up of organic solvent concentrates obtained from a previous SPE method or liquid-liquid extraction. Alumina is used to remove polar species from nonaqueous solutions. Examples include vitamins in feeds and food and antibiotics and other additives from feed. Normal-phase chromatography has been used for a number of years, and most applications for normal-phase column chromatography may be easily transferred over to normal-phase SPE. 

Johnson, R.B. Barnett, H.J. Determination of the fat content in fish feed hy supercritical extraction and subsequent lipid classification of the extract hy thin layer chromatography-flame ionization detection. Aquaculture 2003, 216 l-A), 263-282. 

With the different definitions, different kinds of lipid classification are frequently used in the field. For example, many lipid chemists simply classify lipids into polar and nonpolar lipids based on the overall hydrophobicity of the lipids. The nonpolar lipids include fatty acids and their derivatives (e.g., long-chain alcohols and waxes), glycerol-derived lipids (e.g., monoacylglycerols (MAG), diacylglycerols (DAG),... 

Some key features of this lipid classification, which are adapted in this book, include the following ... 

Lipids are formed from stractural units with a pronounced hydrophobicity. This solubility characteristic, rather than a common structural feature, is unique for this class of compounds. Lipids are soluble in organic solvents but not in water. Water insolubility is the analytical property used as the basis for their facile separation from proteins and carbohydrates. Some lipids are surface-active since they are amphiphilic molecules (contain both hydrophilic and hydrophobic moieties). Hence, they are polar and thus distinctly different from neutral lipids. The two approaches generally accepted for lipid classification are presented in Table 3.1. 

Lipids are present as ingredients in most foods and play key nutritional roles, being crucial for many physiological functions, they also can be used as food quality markers. For these reasons, the characterization of the lipid fraction present in fats and oils is important for the food industry. Following a general lipid classification, triacylglycerols (mono- and diderivatives), phospholipids, glycolipids, waxes, and sterol esters are included in the saponifiable fraction, whereas the nonsaponifiable... 

Pouton, C. Formulation of poorly water-soluble drugs for oral administration Physicochemical and physiological issues and the lipid formulation classification system. Eur. J. Pharm. Sci. 2006, 29, 278-287. 

FIG. 6 Classification of drug delivery sites in lipid bilayers. 

Liposomes are formed due to the amphiphilic character of lipids which assemble into bilayers by the force of hydrophobic interaction. Similar assemblies of lipids form microspheres when neutral lipids, such as triglycerides, are dispersed with phospholipids. Liposomes are conventionally classified into three groups by their morphology, i.e., multilamellar vesicle (MLV), small unilamellar vesicle (SUV), and large unilamellar vesicle (LUV). This classification of liposomes is useful when liposomes are used as models for biomembranes. However, when liposomes are used as capsules for drugs, size and homogeneity of the liposomes are more important than the number of lamellars in a liposome. Therefore, "sized" liposomes are preferred. These are prepared by extrusion through a polycarbonate... 

AC ADME ANS AUC BA/BE BBB BBM BBLM BCS BLM BSA CE CHO CMC CPC CPZ CTAB CV DA DOPC DPPC DPPH aminocoumarin absorption, distribution, metabolism, excretion anilinonaphthalenesulfonic acid area under the curve bioavailability-bioequivalence blood-brain barrier brush-border membrane brush-border lipid membrane biopharmaceutics classification system black lipid membrane bovine serum albumin capillary electrophoresis caroboxaldehyde critical micelle concentration centrifugal partition chromatography chlorpromazine cetyltrimethylammonium bromide cyclic votammetry dodecylcarboxylic acid dioleylphosphatidylcholine dipalmitoylphosphatidylcholine diphenylpicrylhydrazyl... 

Charters, S., Evershed, R. P., Goad, L. J., et al. (1993). Quantification and distribution of lipid in archaeological ceramics implications for sampling potsherds for organic residue analysis and the classification of vessel use. Archaeometry 35 211-223. 

Protein content of field peas is negatively correlated with lipid, cell wall material (CWM), sugar, and ash content and positively correlated with starch separation efficiency and protein separation efficiency in air classification of pea flour. The lower separation efficiency of low protein peas may be due to their high lipid and CWM content which makes disintegration of seeds and separation into protein and starch particles by pin milling difficult. It is suggested that peas with a specific protein content should be used in order to control the protein and starch fraction contents (18). 

SIMCA can be applied to the problem of classification when attempting to correlate measurable effect variables with composition of the classified samples. In correlation analyses one may wish to determine how other sample variables, such as sediment composition, organic content, lipid concentration, etc., influence the composition of measured residues or concentrations of PCBs. 

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