1 -Dipalmitoylphosphatidylcholine

The identity of the moiety (other than glycerol) esterified to the phosphoric group determines the specific phosphoHpid compound. The three most common phosphoHpids in commercial oils are phosphatidylcholine or lecithin [8002-45-5] (3a), phosphatidylethanolamine or cephalin [4537-76-2] (3b), and phosphatidjlinositol [28154-49-7] (3c). These materials are important constituents of plant and animal membranes. The phosphoHpid content of oils varies widely. Laurie oils, such as coconut and palm kernel, contain a few hundredths of a percent. Most oils contain 0.1 to 0.5%. Com and cottonseed oils contain almost 1% whereas soybean oil can vary from 1 to 3% phosphoHpid. Some phosphoHpids, such as dipaLmitoylphosphatidylcholine (R = R = palmitic R" = choline), form bilayer stmetures known as vesicles or Hposomes. The bdayer stmeture can microencapsulate solutes and transport them through systems where they would normally be degraded. This property allows their use in dmg deHvery systems (qv) (8). 

The rate of transport across bilayer membranes reconstituted from dipalmitoylphosphatidylcholine (DPPC) andnigericin is approximately the same as that observed across membranes reconstituted from DPPC and cecropin a at 35 C. Would you expect the transport rates across these two membranes also to be similar at 50 C Explain. 

Lung surfactant is composed mainly of lipid with some proteins and carbohydrate and prevents the alveoli from collapsing. Surfactant activity is largely attributed to dipalmitoylphosphatidylcholine, which is synthesized shortly before parturition in full-term infants. Deficiency of lung surfactant in the lungs of many preterm newborns gives rise to respiratory distress syndrome. Administration of either natural or artificial surfactant has been of therapeutic benefit. 

With nonsupported 1-palmitoylimidazole and DBU, however, a higher yield of the dipalmitoylphosphatidylcholine was obtained (91%). 

Abbreviations. aT = a-tocopherol, AC = aminocoumarin, ANS = l-anilino-8-naphthalenesulfonic acid, CTAB = cetyltrimethylammonium bromide, DPPC = dipalmitoylphosphatidylcholine, DPPH — l,l-diphenyl-2-picrylhydrazyl, DSHA = Ai-dansylhexadecylamine, GMO = glycerol monooleate, HC = hydrocoumarin, N,N -DOC = JV,JV -di(octadecyl)oxacarbocyanine, PC = phosphatidylcholine, p-CUO = pyrene caroboxaldehyde, SDES — sodium decyl sulfate, SDS — sodium dodecyl sulfate, STS = sodium tetradecyl sulfate. 

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... 

Milanowska, J., A. Polit, Z. Wasylewski, and W.I. Gruszecki. 2003. Interaction of isomeric forms of xanthophyll pigment zeaxanthin with dipalmitoylphosphatidylcholine studied in monomolecular layers. J. Photochem. Photobiol. B Biol. 72 1-9. 

Sujak, A., M. Gagos, M.D. Serra, and W.I. Gruszecki. 2007a. Organization of two-component monomolecu-lar layers formed with dipalmitoylphosphatidylcholine and the carotenoid pigment, canthaxanthin. Mol. Membr. Biol. 24 431 141. 

Sujak, A., W. Okulski, and W.I. Gruszecki. 2000. Organisation of xanthophyll pigments lutein and zeaxanthin in lipid membranes formed with dipalmitoylphosphatidylcholine. Biochim. Biophys. Acta 1509 255-263. 

Okulski, W., Sujak, A., and Gruszecki, W.I. 2000. Dipalmitoylphosphatidylcholine membranes modified with zeaxanthin Numeric study of membrane organisation. Biochim. Biophys. Acta 1509 216-228. 

O Leary TJ and Levin IW Raman spectroscopic study of the melting behavior of anhydrous dipalmitoylphosphatidylcholine bilayers. J. Phys. Chem. 1984 88 1790-1796. 

Jizomoto and Hirano [3.41 ] tried to increase the amount of drug inclusions in liposomes by inserting Ca2+ ions in dipalmitoylphosphatidylcholine (DPPC) liposomes. The included volume (mL) per g of liposomes is called Vcap, and this can be increased as a function of the Ca2+ concentration up to ten fold of the minimum Vcap The increase in Vcap is attributed to the electrostatic repulsion between the Ca ions, which reduces the number of lamella and increases the diameter of the liposomes to a certain extent, but increases substantially. A calculated simulation of this thesis is in reasonable agreement with the measurements... 

RA and transmission techniques [3], and applied it to the studies of LB films of cadmium stearate [3], azobenzene-containing long-chain fatty acids and their barium salts [4], dipalmitoylphosphatidylcholine (DPPC) [5], and polyion complexes [6]. Furthermore, we explored the relationship between the molecular orientation evaluated by this method and pyroelectricity in alternating (noncentrosymmetric) Y-type LB films consisting of a phenylpyrazine-containing long-chain fatty acid and deuterated stearic acid and of their barium salts [7]. 

Tieleman, D. P. and Berendsen, H. J. C. (1996). Molecular dynamics simulations of a fully hydrated dipalmitoylphosphatidylcholine bilayer with different macroscopic boundary conditions and parameters, J. Chem. Phys., 105, 4871 —4880. 

Berger, O., Edholm, O. and Jahnig F. (1997). Molecular dynamics simulations of a fluid bilayer of dipalmitoylphosphatidylcholine at full hydration, constant pressure and constant temperature, Biophys. J., 72, 2002-2013. 

Tu, K., Tobias, D. J. and Klein M. L. (1995). Constant pressure and temperature molecular dynamics simulation of a fully hydrated liquid crystal phase dipalmitoylphosphatidylcholine bilayer, Biophys. J., 69, 2558-2562. 

Xiang, T. X. and Anderson, B. D. (1998). Influence of chain ordering on the selectivity of dipalmitoylphosphatidylcholine bilayer membranes for permeant size and shape, Biophys. J., 75, 2658-2671. 

Smejtek, P. and Wang, S. (1991). Domains and anomalous adsorption isotherms of dipalmitoylphosphatidylcholine membranes and lipophilic ions pentachlorophenolate, tetraphenylborate, and dipicrylamine, Biophys. J., 59, 1064-1073. 

In the authors laboratory we have studied the fluorescence depolarization of IR-140 in lipid bilayer membranes of L-a-dipalmitoylphosphatidylcholine (DPPC) and observed similar differences between the gel and liquid crystalline phases as has been widely reported for UV/visible probes such as l,6-diphenyl-l,3,5-hexatriene (DPH) in this same medium. Figure 12.4 shows some of these results. 

M. Vincent, B. de Foresta, J. Gallay, and A. Alfsen, Nanosecond fluorescence anisotropy decays of n-(9-anthroyloxy) fatty acids in dipalmitoylphosphatidylcholine vesicles with regard to isotropic solvents, Biochemistry 21, 708-716 (1982). 

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