Membrane-Water Partitioning of Polychlorinated Biphenyls in Small Unilamellar Vesicles of Four Saturated Phosphatidylcholines

Dulfer, Wiegert J.; Govers, H.A.J.

doi:10.1021/es00010a014

Cited by 53 publications

(63 citation statements)

References 31 publications

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“…84 For anthracene, the published value from the alkane/water system was used. 84 c. Published values, for polychlorinated biphenyls 87 and for other compounds. 82 d. Calculated from equation (10) using the P c/w values and V h /V c volume ratio 2:3.…”

Section: Partitioning Of Chemicalsmentioning

confidence: 99%

Drug-Membrane Interactions Studied in Phospholipid Monolayers Adsorbed on Nonporous Alkylated Microspheres

et al. 2007

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Characterization of interactions with phospholipids is an integral part of the in vitro profiling of drug candidates because of the roles the interactions play in tissue accumulation and passive diffusion. Currently used test systems may inadequately emulate the bilayer core solvation properties (immobilized artificial membranes [IAM]), suffer from potentially slow transport of some chemicals (liposomes in free or immobilized forms), and require a tedious separation (if used for free liposomes). Here the authors introduce a well-defined system overcoming these drawbacks: nonporous octadecylsilica particles coated with a self-assembled phospholipid monolayer. The coating mimics the structure of the headgroup region, as well as the thickness and properties of the hydrocarbon core, more closely than IAM. The monolayer has a similar transition temperature pattern as the corresponding bilayer. The particles can be separated by filtration or a mild centrifugation. The partitioning equilibria of 81 tested chemicals were dissected into the headgroup and core contributions, the latter using the alkane/water partition coefficients. The deconvolution allowed a successful prediction of the bilayer/water partition coefficients with the standard deviation of 0.26 log units. The plate-friendly assay is suitable for high-throughput profiling of drug candidates without sacrificing the quality of analysis or details of the drug-phospholipid interactions.

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Section: Partitioning Of Chemicalsmentioning

confidence: 99%

Drug-Membrane Interactions Studied in Phospholipid Monolayers Adsorbed on Nonporous Alkylated Microspheres

et al. 2007

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“…The partitioning of hydrophobic chemicals has been inversely related to lipid packing densities with unsaturated fatty acids exhibiting greater partitioning (Omann and Lakowicz 1982). In a study of the partitioning of 14 PCBs of varying structures into vesicles of four saturated phosphatidylcholines of varying chain lengths, the fluidity of the membrane bilayer appeared to be more important for the membrane-water partitioning process than the volume of the hydrophobic region, as determined by the membrane lipids alkyl chain length (Dulfer and Govers 1995). Only for PCBs with a large molar volume did steric hindrance appear significant.…”

Section: Temperature Alters Xenobiotic Elimination In Fishmentioning

confidence: 99%

Seasonal influences on PCB retention and biotransformation in fish

James

Kleinow

2013

Environ Sci Pollut Res

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There is extensive evidence that fish from waters with PCB-contaminated sediments accumulate PCBs and related chemicals, and that people who eat fish from contaminated waters have higher body burdens of PCBs and PCB metabolites than those who do not. PCBs and their metabolites are potentially toxic, thus it is important to human health to understand the uptake, biotransformation and elimination of PCBs in fish, since these processes determine the extent of accumulation. The intestinal uptake of PCBs present in the diet of fish into fish tissues is a process that is influenced by the lipid composition of the diet. Biotransformation of PCBs in fish, as in mammals, facilitates elimination, although many PCB congeners are recalcitrant to biotransformation in fish and mammals. Sequential biotransformation of PCBs by cytochrome P450 and conjugation pathways is even less efficient in fish than in mammalian species, thus contributing to the retention of PCBs in fish tissues. A very important factor influencing overall PCB disposition in fish is water temperature. Seasonal changes in water temperature produce adaptive physiological and biochemical changes in fish. While uptake of PCBs from the diet is similar in fish acclimated to winter or summer temperatures, there is evidence that elimination of PCBs occurs much more slowly when the fish is acclimated at low temperatures than at warmer temperatures. Research to date suggests that the processes of elimination of PCBs are modulated by several factors in fish including seasonal changes in water temperature. Thus, the body burden of PCBs in fish from a contaminated location is likely to vary with season.

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“…Above log Kow ~7, the slope of the relationship for polychlorinated biphenyl (PCB) partitioning in liposomes seems to decline, and even become slightly negative. This has been attributed to steric effects in packing of the highly chlorinated congeners (Dulfer and Govers, 1995).…”

Section: Effect Of Contaminant Structurementioning

confidence: 99%

“…This means that among neutral compounds of the same type in a given soil, the equilibrium bioavailability is almost independent of hydrophobic character or molecular log K ow for 33 halogenated hydrocarbons in soil (log K ocw = 0.94 log K ow 0.43), 11 PAHs in soil (log K ocw = 1.14 log K ow 1.02), and 21 polar compounds in soil (log K ocw = 0.73 log K ow 0.52) are from Nguyen et al (2005). The correlation for chlorinated benzenes in DMPC (log K mw = 1.19 log K ow 0.645) is from Gobas et al (1988), for seven chlorinated benzenes in DPPC at 23 o C (log K mw = 0.80 log K ow 0.90) is from van Wezel et al (1996), for fourteen PCBs in DPPC (log K mw = -0.343 (log K ow ) 2 + 5.20 log K ow 12.98) is from Dulfer and Govers (1995), for polar compounds in DMPC (log K mw = 0.904 log K ow + 0.515) is from Vaes et al (1997), and for nonpolar compounds in DMPC (log K mw = 1.05 log K ow 0.324) is from Vaes et al (1997). The correlation for twenty neutral phenols in DOPC/DPPC (8:2 ratio) is the regression line (log K mw = 0.815 log K ow 0.989; r 2 = 0.958) through data tabulated in Escher and Schwarzenbach (1996).…”

Section: Effect Of Contaminant Structurementioning

confidence: 99%