pH-dependent interaction of psychotropic drug with glycerophospholipid monolayers studied by the Langmuir technique

Steinkopf, Signe; Simeunovic, Aida; Bustad, Helene J.; Ngo, Thi Ha; Sveaass, Hege; Gjerde, Anja Underhaug; Holmsen, Holm

doi:10.1016/j.bpc.2010.08.001

Cited by 13 publications

(6 citation statements)

References 33 publications

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“…13,16,39 Additionally, it may be observed in Figure 2b,c that the DPPG monolayers in the presence of chitosan collapse at surface pressures that are increasingly lower than those of pure DPPG, with an increase in pH, thus indicating that they are less stable than the pure monolayers. 10 This in turn further supports the notion that chitosan intercalated the monolayers.…”

Section: ■ Results and Discussionsupporting

confidence: 71%

“…A possible scenario of what happens at the interface is that the interactions lead to the insertion of segments of the polymer chain between the headgroups, inducing a larger separation between them as well as preventing forces between hydrocarbon chains from being operative. Conducive to this action of chitosan should be the loss of its positive charge on approaching pH 6.5, an effect that allows chitosan to become more flexible and to build a thicker adsorption layer with more loops. ,, Additionally, it may be observed in Figure b,c that the DPPG monolayers in the presence of chitosan collapse at surface pressures that are increasingly lower than those of pure DPPG, with an increase in pH, thus indicating that they are less stable than the pure monolayers . This in turn further supports the notion that chitosan intercalated the monolayers.…”

Section: Resultsmentioning

confidence: 53%

“…The technique has been widely applied in studies of various membrane disturbants, such as drugs, , peptides and proteins, , surfactants, and, importantly, polyelectrolytes. − Among the latter chitosan was extensively studied by Pavinatto et al., − however, under one experimental condition of pH and molecular weight of chitosan.…”

Section: Introductionmentioning

confidence: 99%

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Probing the Modes of Antibacterial Activity of Chitosan. Effects of pH and Molecular Weight on Chitosan Interactions with Membrane Lipids in Langmuir Films

2011

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Chitosan, a cationic biopolymer derived from chitin, has been described as having antibacterial activity. The modes of this activity, however, have not been established. One mode proposed is that chitosan perturbs bacterial cell membranes. To validate this proposal, in this study we investigated chitosan interactions with lipids in Langmuir monolayers as model membranes. The interactions were assessed by monitoring differences in the shape of the compression isotherms measured in the absence and presence of chitosan in the subphase (acetate buffer). To appraise the contribution of electrostatic interactions versus hydrogen bonding and hydrophobic interactions, three membrane lipids differing in charge were studied-anionic dipalmitoylphosphatidylglycerol (DPPG), zwitterionic dipalmitoylphosphatidylcholine (DPPC), and neutral cholesterol-and the pH of the subphase was varied between 3.5 and 6.0. In addition, the impact of the molecular weight of chitosan on the interactions was assessed at pH 3.5. It was found that while chitosan had a negligible effect on DPPC monolayers over the pH range studied, it distinctly affected DPPG and cholesterol monolayers. The effect on DPPG was found to decrease with increasing pH, that at pH 3.5 being ascribed to the charge-mediating action of chitosan on the local ionic environment and that at higher pHs to the intercalation of chitosan to the monolayers. Practically independent of pH, the effect of chitosan on cholesterol was accounted for by the formation of cholesterol-chitosan hydrogen bonds. Chitosan of lower molecular weight facilitated the interactions with all the three lipids studied. The results obtained may be helpful in identifying the mode of antibacterial activity of chitosan versus other modes that involve the disturbance of cell life cycles.

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Section: ■ Results and Discussionsupporting

confidence: 71%

Section: Resultsmentioning

confidence: 53%

Section: Introductionmentioning

confidence: 99%

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Probing the Modes of Antibacterial Activity of Chitosan. Effects of pH and Molecular Weight on Chitosan Interactions with Membrane Lipids in Langmuir Films

2011

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“…Evidence from previous monolayer studies revealed that the addition of micromolar concentrations of CPZ can cause a significant expansion of the mean molecular area of the negatively charged phospholipids, but not the neutral glycerophospholipids. 7,8,62,63 Similar conclusions have also been drawn for bilayer samples (liposomes). 5,10,64,65 For the neutral PCs, it has been reported that only the neutral CPZ molecules can be inserted into the lipid bilayer, locating at the hydrophobic tail region, while the protonated CPZ molecules may reside at the lipid−water interface.…”

Section: Dppg Bilayers Reflects Different Interfacial Water Environmentssupporting

confidence: 79%

“…The contrasting SFG results of the PC and PG bilayers interacting with CPZ strongly suggest that there are two different interaction modes between CPZ and the lipid molecules bearing different headgroup structures. Evidence from previous monolayer studies revealed that the addition of micromolar concentrations of CPZ can cause a significant expansion of the mean molecular area of the negatively charged phospholipids, but not the neutral glycerophospholipids. ,,, Similar conclusions have also been drawn for bilayer samples (liposomes). ,,, For the neutral PCs, it has been reported that only the neutral CPZ molecules can be inserted into the lipid bilayer, locating at the hydrophobic tail region, while the protonated CPZ molecules may reside at the lipid–water interface . As a result, the net CPZ concentration within the bilayer is low due to the partial insertion of the CPZ species into the bilayer.…”

Section: Results and Discussionmentioning

confidence: 55%

Investigation of Drug–Model Cell Membrane Interactions Using Sum Frequency Generation Vibrational Spectroscopy: A Case Study of Chlorpromazine

Yang

Zhang

et al. 2014

J. Phys. Chem. C

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Sum frequency generation (SFG) vibrational spectroscopy and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy were applied to study interactions between an antipsychotic agent, chlorpromazine (CPZ), and model cell membranes consisting of either distearoylphosphatidylcholine (DSPC) or dipalmitoylphosphatidylglycerol (DPPG). The PC and PG lipids represent the zwitterionic and anionic components of the cell membranes, respectively. For an isotopically asymmetric bilayer composed of a deuterated lipid leaflet and a hydrogenated lipid leaflet, the time-dependent SFG signals from the lipids revealed that CPZ can significantly accelerate the flip-flop process of the neutral DSPC bilayer and such an acceleration effect is more pronounced at higher CPZ concentrations. While for the negatively charged DPPG bilayer, it was found that CPZ molecules can immediately bind to and disrupt the outer lipid leaflet and then gradually reduce the ordering of the inner lipid leaflet. A higher CPZ concentration in the subphase leads to a faster disordering effect on the inner leaflet. The association of CPZ to the lipid membranes can be verified by the change in the SFG spectra of the OH stretching vibration of the interfacial water molecules. ATR-FTIR results revealed that addition of CPZ to the subphase did not exert significant effect on the dDSPC/dDSPC bilayer, especially at low CPZ concentrations (<2 mM). It was found that CPZ can cause gel-to-fluid phase transition of the dDPPG/dDPPG bilayer at CPZ concentrations below 2 mM, and higher CPZ concentrations can lead to dissolution of the bilayer. This work demonstrated that SFG (along with ATR-FTIR) is a powerful in situ and label-free technique that can be used to study various aspects of the drug–membrane interactions at the molecular level.

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The influence of plant stanol (β-sitostanol) on inner leaflet of human erythrocytes membrane modeled with the Langmuir monolayer technique

Hąc-Wydro

Lenartowicz

Dynarowicz-Łątka

2013

Colloids and Surfaces B: Biointerfaces

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pH-dependent interaction of psychotropic drug with glycerophospholipid monolayers studied by the Langmuir technique

Cited by 13 publications

References 33 publications

Probing the Modes of Antibacterial Activity of Chitosan. Effects of pH and Molecular Weight on Chitosan Interactions with Membrane Lipids in Langmuir Films

Probing the Modes of Antibacterial Activity of Chitosan. Effects of pH and Molecular Weight on Chitosan Interactions with Membrane Lipids in Langmuir Films

Investigation of Drug–Model Cell Membrane Interactions Using Sum Frequency Generation Vibrational Spectroscopy: A Case Study of Chlorpromazine

The influence of plant stanol (β-sitostanol) on inner leaflet of human erythrocytes membrane modeled with the Langmuir monolayer technique

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