DPPC dipalmitoyl phosphatidylcholine

Since optical measurements of monolayers at the water-oil interface are rather difficult to carry out, a configuration was suggested where a monolayer at the water-air interface was in contact with an oil lens which was partly wetting the monolayer [23]. The thermodynamic relation between this monolayer and that residing at the water-oil interface was discussed. This configuration was utilized in the X-ray diffraction experiments [24] where the structural changes of dipalmitoyl phosphatidylcholine (DPPC) and DPPE were followed. 

Cantrell et al. (2003) studied the quenching of 02 by several dietary carotenoids in dipalmitoyl phosphatidylcholine (DPPC) unilamellar liposomes. These workers used water soluble and lipid soluble 02 sensitizers so that a comparison of the efficiencies of quenching 02 generated within and outside the membrane model could be made. Perhaps surprisingly there was little difference in the efficiency of quenching in either situation. Typical results are presented in Table 14.3 (taken from Cantrell et al. (2003 and 2006)). 

Fig. 2. Phase diagram describing lateral phase separations in the plane of bilayer membranes for binary mixtures of dielaidoylphosphatidylcholine (DEPC) and dipalmitoyl-phosphatidylcholine (DPPC). The two-phase region (F+S) represents an equilibrium between a homogeneous fluid solution F (La phase) and a solid solution phase S presumably having monoclinic symmetry (P(J. phase) in multilayers. This phase diagram is discussed in Refs. 19, 18, 4. The phase diagram was derived from studies of spin-label binding to the membranes.

Helm et al. [443] subsequently studied dipalmitoyl phosphatidylcholine (DPPC). They concluded that the condensed two-dimensional phase normally involves a tilt of the hydrocarbon chains of about 30°... 

Figure 1 Experimentally determined values of ko obtained employing 3-methylindole as the quencher in homogeneous solvents, plotted as a function of the wavelength of maximum fluorescence intensity (data from Ref. 14). kap values determined in DODAC LUVs ( ) and in dipalmitoyl phosphatidylcholine (DPPC) LUVs (A) have been included. Also are included the experimentally determined value of kap in sodium dodecyl sulfate micelles ( ) and the value of kQ estimated from Eq. (21) ( ).

Liposomes made of pure phospholipids will not form at temperatures below T of the phospholipid. This temperature requirement is reduced to some extent, but not eliminated, by the addition of cholesterol (17). In some cases, it is recommended that liposome preparation be carried out at temperatures well above T of the vesicles. For instance, in the case of vesicles con-taining dipalmitoyl phosphatidylcholine (DPPC, T = 41°C), it has been suggested that the liposome preparation procedure be carried out at 10°C higher than the T at 51°C (18, 19). This is in order to make sure that all the phospholipids are dissolved in the suspension medium homogenously and have sufficient flexibility to align themselves in the structure of lipid vesicles. Following termination of the preparation procedure, usually nanoliposomes are allowed to anneal and stabilize for certain periods of time (e.g. 30-60 min), at a temperature above T, before storage. 

With respect to safety and the use of phospholipids, no NDA-supporting chronic inhalation studies have been conducted except for those found in commercial pulmonary surfactants. These studies presumably will have involved intratracheal instillation and not aerosolization, since the primary indication is respiratory distress syndrome of the newborn. Nevertheless, the fact that these products are available suggests that synthetic versions of natural lipids such as dipalmitoyl phosphatidylcholine (DPPC) and dipalmitoyl phosphatidylglycerol (DPPG) are likely to be well tolerated. This assumption has been supported from subchronic aerosol studies in mice [60] and acute single-dose aerosol studies in man, the latter involving soy-derived phosphatidylcholines [61]. 

Lipids are building blocks of model and real membranes, which can be combined with proteins and some other important biomolecules to simulate real membranes. The simplest model is hence the self-assembly of only one component of the complex membrane, in this case the lipids. These mono-component lipidic models are often employed in studies as their interaction with small molecules mimics the actual relationship between the cell membrane and a substrate. A commonly employed amphiphatic lipid, dipalmitoyl phosphatidylcholine (DPPC) (Figure 4.6.2), has been widely used to construct these cell membrane motifs, due to its high content in animal cells, and thus its tendency to mimic a valid animal ceU. The supramolecular organization of these (a) DPPC amphiphatic molecules lead to a (b) Langmuir monolayer, (c) bilayer, (d) micelle, and (e) vesicle, which are the available levels of modeling to mimic the cellnlar membrane. 

Figure 4.6.2 The chemical structure of a dipalmitoyl phosphatidylcholine (DPPC) amphiphatic lipid and its organization in model membranes...

Colfosceril palmitate (dipalmitoyl-phosphatidylcholine (DPPC)) Exosurf Neonatal (Glaxo Wellcome) 5 to 7 drug 13.5 cetyl alcohol 1.5 tyloxapol 1 sodium chloride (O.IN) 235-236 (R-form) V 9.81 intratracheal... 

GlvcoDhorin-Lioid Monolayers at the Air-Water Interface. Further to the study of pure glycophorin monolayers we investigated the interaction between the glycophorin and dipalmitoyl-phosphatidylcholine (DPPC) in mixed monolayers at the air-water interface (27). Pure DPPC undergoes the characteristic liquid expanded (L ) to intermediate state (I) transition in monolayers at temperatures below the chain-melting temperature (- 42 C) of... 

Since DAGs with diC are the most effective activators of protein kinase C it was concluded that the activation of the enzyme occurs via a transverse perturbation of the lipid bilayer structure [72]. H-NMR spectra of dipalmitoyl-phosphatidylcholine (DPPC) in the absence and presence of DAGs of various chain lengths are depicted in Figure 11-7. 

Figure 9.1 Molecular structure of dipalmitoyl phosphatidylcholine (DPPC) and diphytanoyl phosphatidylcholine (DPhPq.

Synonyms L-a-1,2-Dipalmitoyl phosphatidylcholine DPPC Uses Emulsifier, solubilizer for dermatology and cosmetics for mfg. of liposomes and mixed micelles Manuf./Distrib. Genzyme http //www.genzyme. com Trade Name Synonyms Phospholipon PC t[Am. Lecithin... 

Abstract The miscibility of two phospholipids dipalmitoyl-phosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) possessing both a choline head group, with per-(6-dodecanoylamino-6-deoxy) j8-cyclodextrin (CnCONH-/ -CD) and poly(ethylene oxide)-bearing lipid (PEO-lipid), respectively, has been assessed by surface pressure measurements of binary monolayers under dynamic conditions. Although the four studied amphiphiles had similar hydrophobic moieties constituted of hydrocarbon units with the number of carbons ranging from 12 to 16, PEO-lipid markedly differed from other amphiphiles due to its bulky poly(ethylene oxide) chain containing 13 ethylene oxide units totally immersed in the aqueous subphase. The additivity rule applied to these binary mixtures clearly showed that molecular areas for both systems deviated from linearity. For... 

These criteria prompted us to review and to compare two systems recently studied by us in which mixed mono-layers were formed with either amphiphilic cyclodextrins or poly(ethylene oxide)-bearing lipids and phospholipids [9-12]. The phospholipids simultaneously deposited with either per-(6-dodecanoylamino-6-deoxy) jS-cyclodextrin (CiiCONH-jS-CD) or poly (ethylene oxide)-bearing lipid (PEO-lipid) to form mixed monolayers were dipalmitoyl-phosphatidylcholine (DPPC) and dimyristoylphos-phatidylcholine (DMPC), respectively. 

Figure 5.3. Dipalmitoyl phosphatidylcholine (DPPC) transferred on to a solid support at a rather high transfer speed of 1000 pm/s at a lateral surface pressure of 3.0 mN/m Dynamic scanning force microscopy (SFM) images provide evidence for the formation of a regularly structured surface, revealing channels with a width of about 200 nm separated by 800 nm wide stripes of the monomolecular film. The main figure represents phase and and the inset (4x4 pm ) topography imaging. The monolayer was prepared on pure water at room temperature A change in the temperature influences the periodicity. (From M. Gleiche and L. F. Chi), Nature, 403, 2000, 173)...

Fig. 20 O Is, N Is, and C Is peaks of maltodextrin and poly(L -serine) [SSX 100/206 spectrometer, monochromatized AIko, pass energy 50eV, Gaussian/Lorentzian ratio 85/15], and type I collagen and dipalmitoyl phosphatidylcholine (DPPC) [Kratos Axis Ultra spectrometer, monochromatized AIro, pass energy 40 eV, Gaussian/Lorentzian ratio 70/30]...

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