Lipids glycerides

Hydrolysis is the other important mechanism for some lipids (glycerides and phosphoglycerides) to degrade. Lowering of pH can arise from both hydrolysis and lipid peroxidation (Arakane et al., 1995), as both processes can give acid products. It has also been reported that hydrolysis and peroxidation can act in synergy with one another in liposome bilayers (Swern, 1995), but it is uncertain whether this can happen for other structures since different mechanisms are operative for... 

As mentioned, hydrolysis is the other important mechanism by which some lipids (glycerides and phosphoglycerides) degrade and can lead to a reduction in pH due to liberation of free fatty acids this was discussed in Chapter 10 (Part I Parenteral Application). This phenomenon is less important for oral formulations when compared to parenteral products, since the former generally have low amounts of water in the formulation. Hydrolysis could occur on storage if water is absorbed from or through the gelatin shell. 

Fats and fat-like compounds of varying chemical structures are classified as lipids. They have a low molecular weight and are insoluble in water. The original substance in fat biosynthesis is acetyl-CoA (so-called activated acetic acid). On the basis of chemical criteria, they may be divided into simple lipids (glycerides, cholesterol, cholesterol esters, bile acids) and complex lipids, (s. tab. 3.7)... 

The use of radioactive tracers in the study of reaction mechanisms has been steadily increasing over the last two decades. Radioactive tracers have been used to elucidate the mechanism of complex laboratory reactions, in photosynthetic chemistry and, in particular, to follow metabolic pathways of substances, synthetic and natural, in both plants and animals. In fact, the first reported use of an in-line radioactivity detector fitted directly to a gas chromatograph was in a paper by James and Piper (51) who developed the detector to study the synthesis of lipids, glycerides and fatty acids in plant tissue. James and his... 

Fatty acid Total lipids Cholesterol esters Phospho- lipids Glycerides Free fatty acids... 

CifiHjjOi. A fatly acid which is easily oxidized in air.-It occurs widely, in the form of glycerides, in vegetable oils and in mammalian lipids. Cholesieryl linoleale is an important constituent of blood. The add also occurs in lecithins. Together with arachidonic acid it is the most important essential fatty acid of human diet. 

Lipoproteins. The lipid moiety of lipoproteins is quite variable both qualitatively and quantitatively. The a-lipoprotein of serum contains glyceride, phosphatide and cholesterol to about 30 -40% of the total complex. The -lipoprotein of serum contains some glyceride but the phosphatide and cholesterol account for nearly 75% of the total. 

The yolk is separated from the white by the vitelline membrane, and is made up of layers that can be seen upon careful examination. Egg yolk is a complex mixture of water, Hpids, and proteias. Lipid components iaclude glycerides, 66.2% phosphoUpids, 29.6% and cholesterol [57-88-5] 4.2%. The phosphohpids consist of 73% lecithin [8002 3-5] 15% cephahn [3681-36-7], and 12% other phosphohpids. Of the fatty acids, 33% are saturated and 67% unsaturated, including 42% oleic acid [112-80-1] and 7% linoleic acid [60-33-3]. Fatty acids can be changed by modifying fatty acids ia the laying feed (see... 

Rhodamine 6G long-chain hydrocarbons [169] squalene, a-amyrin [170] methyl esters of fatty acids [171] glycerides [91] sterols [172, 173] isoprenoids, quinones [HI] lipoproteins [174] glycosphingolipids [175] phenolic lipids [176] phosphonolipids [177] increasing the sensitivity after exposure to iodine vapor [178,179]... 

Because they are uncharged, acylglycerols (glycerides), cholesterol, and cholesteryl esters are termed neutral lipids. 

Although not very commonly used in the separation of nentral hpids, two-dimensional systems have been nsed to separate hydrocarbons, steryl esters, methyl esters, and mixed glycerides that move close to each other in one-dimensional systems. Complex neutral lipids of Biomphalaria glabrata have been first developed in hexane diethyl ether (80 20), dried, and the plates have been turned 90°, followed by the second development in hexane diethyl ether methanol (70 20 10) for complete separation of sterol and wax esters, triglycerides, free fatty acids, sterols, and monoglycerides [54]. 

Lipids in living systems are by solvents extractable compounds. Among the lipids are the fatty acids, glycerides, steroids, terpenes, and complex lipids as lipoproteins. 

CAPRYLIC/CAPRIC GLYCERIDES, COSMETICALLY USEFUL LIPID... 

Caprylic/capric glycerides, cosmetically useful lipid, 7 833t... 

Hydrogenated MDI (HMDI), 25 463 Hydrogenated palm kernel glycerides, cosmetically useful lipid, 7 833t Hydrogenated polyisobutene, in mascara, 7 862... 

The partition of different lipids between two immiscible solvents (countercurrent distribution) is useful for crude fractionation of lipid classes with greatly differing polarities. Repeated extractions in a carefully chosen solvent pair increase the effectiveness of the separation but in practice mixtures of lipids are still found in each fraction. A petroleum ether-ethanol-water system can be used to remove polar contaminants (into the alcoholic phase) when interest lies in the subsequent analysis of neutral glycerides, which may be recovered from the ether phase. Carbon... 

Extraction of lipids from muscle foods is more predictable if the food has less than 10% moisture. Higb recoveries of glycerides can be obtained from dry meat products by extracting with SC-CO2 above 300 bar, but cholesterol is extracted less effectively. Cholesterol is extracted from beef tallow more efficiently at lower pressures than at higher pressures (<300 bar). 

Breckenridge, W. C. 1978. Stereospecific analysis of triacylglycerols. In Handbook of Lipid Research, Vol. I Fatty Acids and Glycerides. A. Kuksis (Editor). Plenum Press, New York pp. 197-232. 

Bus, J., Luk, C. M. and Gruenewegen, A. 1976. Determination of enantiomeric purity of glycerides with a chiral PMR shift reagent. Chem. Phys. Lipids 16, 123-132. 

Kuksis, A. 1972. Newer developments in determination of structure of glycerides and phosphoglycerides. In Progress in the Chemistry of Fats and Other Lipids, Vol. 12. R.T. Holman (Editor). Pergamon Press, New York, p. 82. 

Tanioka, H., Lin, C. Y., Smith, S. and Abraham, S. 1974. Acyl specificity in glyceride synthesis by lactating rat mammary gland. Lipids 9, 229-234. 

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