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Antibodies to Lipids and Lipid Membranes: Reactions with Phosphatidylcholine, Cholesterol, Liposomes and Bromelin-Treated Erythrocytes
Published in E. Nigel Harris, Thomas Exner, Graham R. V. Hughes, Ronald A. Asherson, Phospholipid-Binding Antibodies, 2020
The concept introduced by Sachs and Klopstock that purified lecithin could serve as an antigen was challenged by Levene, Landsteiner and van der Scheer.28 These latter authors confirmed the finding of Sachs and Klopstock that Merck egg lecithin could be used as an antigen. However, satisfactory antisera were not produced by injection of egg lecithin, brain lecithin, or hydrogenated lecithin prepared by the authors themselves. One antiserum reacted with the Merck lecithin but not with the authors’ egg lecithin used for immunization. The authors concluded that either the antibodies depended on unique physicochemical properties of the Merck lecithin, or the antibodies were not actually produced against lecithin but against a contaminant that was present in the Merck lecithin.
Antifungals
Published in Rajendra Prasad, Mahmoud A. Ghannoum, Lipids of Pathogenic Fungi, 2017
A. S. Ibrahim, R. Prasad, M. A. Ghannoum
Factors other than sterols have also been shown to play a role in polyene sensitivity of yeast cells.31,33 Hsu Chen and Feingold34 reported that the presence of cholesterol in liposomes derived from egg lecithin was more sensitive to nystatin or amphotericin B than those derived from dipalmitoyl or distearoyl lecithins. Thus, it appears that polyene antibiotic toxicity may also depend on the fatty acyl composition of the phospholipids. The correlation between polyene sensitivity of different cell lines and the cholesterol:phospholipid molar ratio reflects a relationship between sensitivity and membrane fluidity. Any change in this ratio is expected to affect the internal viscosity and molecular motion of lipid within membranes, which may result in the differences in sensitivity of cells to polyenes. Oxidative damage by polyenes is yet another factor suggested to contribute to the killing of C. albicans?5’™ The reader is referred to chapter 12 for full discussion of the interaction of polyenes with lipids.
Lingual Lipase
Published in Margit Hamosh, Lingual and Gastric Lipases: Their Role in Fat Digestion, 2020
Lecithin, the major dietary phospholipid, inhibits the action of pancreatic lipase by preventing the binding between enzyme and the triglyceride substrate. Incubation of lingual lipase in the presence of increasing amounts of lecithin did not affect the hydrolysis of triolein, indicating that this enzyme will maintain its activity when a mixture of different lipids are present (Table 15). These findings have been confirmed and extended by Roberts et al., who compared the effect of medium-chain (dihexanoyl) lecithin or natural (egg yolk) lecithin on the activities of lingual and pancreatic lipases (Figures 42 and 43). Their study shows that dihexanoyl lecithin markedly inhibits the activity of pancreatic lipase when present at a concentration of 0.1 mM, and completely inhibits activity at 10 mM. In contrast, the activity of lingual lipase was only slightly inhibited at the highest dihexanoyl lecithin concentration. When the lingual lipase preparation was solubilized in 0.1% Triton® X-100 (inset), activities were 25-fold greater, and further activation of the enzyme was induced by low concentrations of lecithin. Analogous studies with long-chain egg lecithin (Figure 43) gave similar results with the exception that pancreatic lipase was completely inhibited by 1 mM egg lecithin, whereas lingual lipase showed slight but progressive activation in the presence of up to 30 mM lecithin. These investigators also made the observation that the addition of purified colipase restored pancreatic lipase activity fully but was without effect on the activity of lingual lipase. The data show that the displacing effect of amphiphiles (such as phospholipids or bile salts), which results in the inhibition of pancreatic lipase, can be reversed by equimolar concentrations of colipase which binds the enzyme to the amphiphile-covered interface.170 Roberts and colleagues speculate that the hydrophobicity of lingual lipase may allow it to bind to triglyceride substrate more rapidly (contrary to the hydrolysis of triglyceride by pancreatic lipase, there is no lag period during the hydrolysis of triglyceride by lingual lipase) than pancreatic lipase and to resist the surfactant desorption of surface active agents.142 We have suggested that because lingual lipase neither hydrolyzes nor is inhibited by phospholipids, it can penetrate lecithin-coated emulsions or fat particles and hydrolyze the triglyceride within.156, 174
Rationale utilization of phospholipid excipients: a distinctive tool for progressing state of the art in research of emerging drug carriers
Published in Journal of Liposome Research, 2023
Koilpillai Jebastin, Damodharan Narayanasamy
Egg lecithin is a natural phospholipid and it can be used as emulsifying agent in the development of Nanoemulsions (Dammak et al. 2020). Using phospholipid vesicle consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1,2-dioleoyl-sn-glycerophosphocholine (DOPC), water-insoluble genistein can be solubilized in aqueous medium (Yamamoto et al. 2019). Phosphatidylcholines are crucial excipients in the development of liposomes and other lipid-based products, such as mixed micelles in pharmaceutical formulations (Rupp et al. 2010). In keeping with the pharmaceutical approach, phospholipids will be used as essential excipients for parenteral drug products and as solubilizing agents for formulations, such as liposomes and their derived colloidal vesicles, oil-in-water emulsions, and mixed micelles. Phospholipids can be used to reduce the gastrointestinal side effects of Non-steroidal anti-inflammatory drugs (NSAIDs) and as a solubilizing agent to help poorly water-soluble drug molecules be better absorbed following oral administration (Driscoll 2006, Shah et al. 2010, Hoogevest 2020).
Brain targeting of agomelatine egg lecithin based chitosan coated nanoemulsion
Published in Pharmaceutical Development and Technology, 2021
Marwa Hassan Shukr, Omar A. Ahmed Farid
At nasal pH (5.5–6.5), cationic polymers that coating the surface of NE will exist in ionized form, thus positively charged groups on deacetylated N-acetyl groups will allow electrostatic interaction with negatively charged mucus. ZP significantly affected the drug residence on the nasal mucosa, as the positively charged chitosan coated globules are better attached by electrostatic interactions to the negatively charged mucin (Harding 2006). The observed decrease in ZP by increasing ratio of egg lecithin: oil from 1:10 to 3:10 could be explained due to the presence of negatively charged phospholipids and free fatty acids present in egg-lecithin (Yang and Benita 2000; Fasolo et al. 2009). Polynomial analysis fitted with linear model was adopted for analysis of the ZP with non-significant lack of fit (p = 0.7902). The value of the adequate precision was 7.91, which indicate adequacy of the ratio of signal to noise. Moreover, the reasonable agreement between the predicted (0.8127) and adjusted (0.8779) R2 values confirmed strong model validity. Figure 3 showed that an increase in the ZP values by increasing chitosan concentration (B). The following equation express the predicted ZP values:
Optimization, and in vitro and in vivo evaluation of etomidate intravenous lipid emulsion
Published in Drug Delivery, 2021
Dandan Geng, Yan Li, Chunyan Wang, Bo Ren, Heping Wang, Chensi Wu, Yirong Zhang, Linlin Zhao, Ligang Zhao
Soybean phospholipid, egg lecithin, and F68 were evaluated as potential emulsifiers for this formulation. Both soybean phospholipids and egg lecithin are derived from natural sources. There was little difference in the appearance, particle size, and PDI of the emulsions prepared using these two emulsifiers, but the ETM-ILE prepared using egg lecithin exhibited a higher ZP. Emulsification using F68 was very slow, but it could stabilize the phase-interfaces in the emulsion (Powell et al., 2017). In addition, F68 had an effect on the treatment of vascular occlusion caused by blood cell aggregation, and could also promote drug transport across the blood-brain barrier, thus increasing drug bioavailability in the brain (Agrawal et al., 2015). Therefore, egg lecithin and F68 were selected as the emulsifiers for use in this study.