Article

The membrane-activity of Ibuprofen, Diclofenac, and Naproxen: A physico-chemical study with lecithin phospholipids

Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, A.A. 1226, Medellín, Colombia.
Biochimica et Biophysica Acta (Impact Factor: 4.66). 03/2009; 1788(6):1296-303. DOI: 10.1016/j.bbamem.2009.01.016
Source: PubMed

ABSTRACT

Nonsteroidal anti-inflammatory drugs (NSAIDs) represent non-specific inhibitors of the cycloxygenase pathway of inflammation, and therefore an understanding of the interaction process of the drugs with membrane phospholipids is of high relevance. We have studied the interaction of the NSAIDs with phospholipid membranes made from dimyristoylphosphatidylcholine (DMPC) by applying Fourier-transform infrared spectroscopy (FTIR), Förster resonance energy transfer spectroscopy (FRET), differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC). FTIR data obtained via attenuated total reflectance (ATR) show that the interaction between DMPC and NSAIDs is limited to a strong interaction of the drugs with the phosphate region of the lipid head group. The FTIR transmission data furthermore are indicative of a strong effect of the drugs on the hydrocarbon chains inducing a reduction of the chain-chain interactions, i.e., a fluidization effect. Parallel to this, from the DSC data beside the decrease of T(m) a reduction of the peak height of the melting endotherm connected with its broadening is observed, but leaving the overall phase transition enthalpy constant. Additionally, phase separation is observed, inducing the formation of a NSAID-rich and a NSAID-poor phase. This is especially pronounced for Diclofenac. Despite the strong influence of the drugs on the acyl chain moiety, FRET data do not reveal any evidence for drug incorporation into the lipid matrix, and ITC measurements performed do not exhibit any heat production due to drug binding. This implies that the interaction process is governed by only entropic reactions at the lipid/water interface.

Download full-text

Full-text

Available from: Marcela Manrique-Moreno, Jul 23, 2014
  • Source
    • "In the following study, we propose a new versatile approach for analyzing PEGylated conjugate composition based on FTIR spectroscopy. FTIR is robust and highly informative method for studying the structure and composition of biomolecules19202122. The important advantage of the proposed approach over existing methods is the possibility to analyze samples in solution, in suspension, as well as in other heterogeneous and microheterogeneous systems such as polymeric micelles, liposomes, hydrogels, and others. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Here we report a new approach based on FTIR-spectroscopy for determining the degree of PEGylation in biomolecules. We show that the PEG C-O-C peak (at 1089 cm−1) is the main analytically valuable band in IR spectra of PEG-containing systems: it is narrow and highly intense, it is well distinguished from absorption bands of other principal functional groups of proteins and other biopolymers (carbonyl, amide, hydroxyl etc), and therefore is easily identified in the IR spectra. The proposed method is therefore “reagent-free” and allows for fast and accurate determination of the PEGylation degree of biomolecules as well as the structural characteristics of bioconjugates from a single FTIR spectrum. The measurement is not dependent on PEG polymerization degree or branching and can be applied in a wide pH range, making it a convenient replacement of laborious and unreliable methods. The developed approach was successfully used to study the range of PEG-containing covalent conjugates with chitosan and non-covalent complexes with anionic liposomes. The composition of PEG-chitosan conjugates as well as their storage stability was determined by the method based on FTIR-spectroscopy. In the case of non-covalent complexes, not only PEG content, but also the binding constants of PEG-containing ligands to the liposome membrane were evaluated with this approach. The results obtained by the FTIR method were confirmed by DLS and zeta-potential experiments where the formation of electrostatic complex was monitored by the increase in the particle radius (from 80 nm to 105 nm) and zeta-potential neutralization (from −20 mV to −12 mV). Direct comparison of the results of FTIR approach with that of TNBS or OPA titration methods shows very good agreement between the measurements, with the FTIR method showing much lower deviation.
    Full-text · Article · Jan 2016 · Colloids and surfaces B: Biointerfaces
  • Source
    • "One of the alternative mechanisms by which NSAIDs can affect both biological and cytotoxic responses is by interacting with cellular membranes and altering their biophysical properties. In support of this possibility, our and other laboratories have reported that NSAIDs can induce changes in the fluidity, permeability and biomechanical properties of cell membranes [22] [23] [24] [25] [26] [27] [28] [29]. In this report we have extended these studies by investigating the interaction of NSAIDs (specifically Biochimica et Biophysica Acta 1821 (2012) 994–1002 ⁎ Corresponding author at: Department of Integrative Biology & Pharmacology, The "
    [Show abstract] [Hide abstract]
    ABSTRACT: Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most widely consumed pharmaceuticals, yet both the mechanisms involved in their therapeutic actions and side-effects, notably gastrointestinal (GI) ulceration/bleeding, have not been clearly defined. In this study, we have used a number of biochemical, structural, computational and biological systems including; Fourier Transform InfraRed (FTIR). Nuclear Magnetic Resonance (NMR) and Surface Plasmon Resonance (SPR) spectroscopy, and cell culture using a specific fluorescent membrane probe, to demonstrate that NSAIDs have a strong affinity to form ionic and hydrophobic associations with zwitterionic phospholipids, and specifically phosphatidylcholine (PC), that are reversible and non-covalent in nature. We propose that the pH-dependent partition of these potent anti-inflammatory drugs into the phospholipid bilayer, and possibly extracellular mono/multilayers present on the luminal interface of the mucus gel layer, may result in profound changes in the hydrophobicity, fluidity, permeability, biomechanical properties and stability of these membranes and barriers. These changes may not only provide an explanation of how NSAIDs induce surface injury to the GI mucosa as a component in the pathogenic mechanism leading to peptic ulceration and bleeding, but potentially an explanation for a number of (COX-independent) biological actions of this family of pharmaceuticals. This insight also has proven useful in the design and development of a novel class of PC-associated NSAIDs that have reduced GI toxicity while maintaining their essential therapeutic efficacy to inhibit pain and inflammation.
    Full-text · Article · Apr 2012 · Biochimica et Biophysica Acta
  • Source
    • "Our results show that both ligands lower the main phase transition temperature of the DPPC membrane bilayer, as indicated by the presence of liquid crystal features within the 2 H spectra at temperatures below 41.5 °C. This effect, frequently found for many anesthetics [34] [35] [36], has also been observed with other cannabinoids [4] [37]. Additionally, the phase transition of the phospholipid bilayer accompanying reduction in temperature is significantly ligand dependent. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Two key commonly used cannabinergic agonists, CP55940 and WIN55212-2, are investigated for their effects on the lipid membrane bilayer using (2)H solid state NMR, and the results are compared with our earlier work with delta-9-tetrahydrocannabinol (Δ(9)-THC). To study the effects of these ligands we used hydrated bilayers of dipalmitoylphosphatidylcholine (DPPC) deuterated at the 2' and 16' positions of both acyl chains with deuterium atoms serving as probes for the dynamic and phase changes at the membrane interface and at the bilayer center respectively. All three cannabinergic ligands lower the phospholipid membrane phase transition temperature, increase the lipid sn-2 chain order parameter at the membrane interface and decrease the order at the center of the bilayer. Our studies show that the cannabinoid ligands induce lateral phase separation in the lipid membrane at physiological temperatures. During the lipid membrane phase transition, the cooperative dynamic process whereby the C-(2)H segments at the interface and center of the bilayer spontaneously reach the fast exchange regime ((2)H NMR timescale) is distinctively modulated by the two cannabinoids. Specifically, CP55940 is slightly more efficient at inducing liquid crystalline-type (2)H NMR spectral features at the membrane interface compared to WIN55212-2. In contrast, WIN55212-2 has a far superior ability to induce liquid crystalline-type spectral features at the center of the bilayer, and it increases the order parameter of the sn-1 chain in addition to the sn-2 chain of the lipids. These observations suggest the cannabinoid ligands may influence lipid membrane domain formations and there may be contributions to their cannabinergic activities through lipid membrane microdomain related mechanisms. Our work demonstrates that experimental design strategies utilizing specifically deuterium labeled lipids yield more detailed insights concerning the properties of lipid bilayers.
    Preview · Article · Dec 2010 · Biochimica et Biophysica Acta
Show more