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The effect of three phosphonium and imidazolium ionic liquids (ILs) on the interaction between liposomes and common pharmaceuticals found in wastewaters was studied. The liposomes comprised zwitterionic phosphatidyl choline and negatively charged phosphatidyl glycerol. A set of common cationic, anionic, and neutral compounds with varying chemical composition and unique structures were included in the study. The electrophoretic mobilities of the analytes were determined using conventional capillary electrophoresis (CE), using CE under reversed electroosmotic flow mobility conditions, and in the presence of ILs in the background electrolyte (BGE) solution by electrokinetic chromatography (EKC). In order to evaluate the impact of ILs on the interaction between the compounds and the liposomes, EKC was performed with liposome dispersions, with and without ILs. The retention factors of the compounds were calculated using BGEs including liposome dispersions with and without ILs. Two phosphonium based ILs, namely tributyl(tetradecyl)phosphonium chloride ([P14444]Cl) and octyltributylphosphonium chloride ([P8444]Cl), were chosen due to their long alkyl chains and their low aggregation concentrations. Another IL, i.e. 1-ethyl-3-methylimidazolium acetate ([emim][OAc]), was chosen based on our previous study, which suggests that it has a minimal or even nonexistent effect on liposomes at the used concentrations. The results indicate that the studied ILs have an effect on the interactions between wastewater compounds and liposomes, but the effect is highly dependent on the concentration of the IL and on the IL alkyl chain lengths. Most of the ILs hindered the interactions between the liposomes and the compounds, indicating strong interaction between ILs and liposomes. In addition, the nature of the studied compounds themselves affected the interactions., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The toxicity of some promising biomass-dissolving amidinium-, imidazolium-, and phosphonium-based ionic liquids (ILs), toward two different cell lines, human corneal epithelial cells and Escherichia coli bacterial cells, was investigated. In addition, dynamic light scattering (DLS) and ζ potential measurements were used to study the effect of the ILs on the size and surface charge of some model liposomes. Capillary electrophoresis (CE) was used for determination of the electrophoretic mobilities of the liposomes and for determination of the critical micelle concentration (cmc) of the ILs. The toxicity of the phosphonium ILs was highly dependent on the longest linear chain of the IL, due to increasing hydrophobicity, with the long-chain phosphonium ILs being toxic while the shorter-chain versions were significantly less toxic or not toxic at all. Amidinium and imidazolium ILs showed no significant effect on the cells, within the concentration range used. Moreover, the more hydrophobic ILs were found to have a major effect on the surface charges and size distributions of the model liposomes, which can lead to disruption of the lipid bilayer. This indicates that the cytotoxicity is at least to some extent dependent on direct interactions between ILs and the biomembrane.

Bupivacaine is a lipophilic, long-acting, amide class local anesthetic commonly used in clinical practice to provide local anesthesia during surgical procedures. Several cases of accidental overdose with cardiac arrest and death have been reported since bupivacaine was introduced to human use. Recent case reports have suggested that Intralipid (Fresenius Kabi) is an effective therapy for cardiac toxicity from high systemic concentrations of, e.g. bupivacaine, even though the mechanism behind the interaction is not fully clear yet. Our long-term aim is to develop a sensitive, efficient, and non-harmful lipid-based formulation to specifically trap harmful substances in vivo. In this study, the in vitro interaction of local anesthetics (bupivacaine, prilocaine, and lidocaine) with Intralipid or lipid vesicles containing phosphatidylglycerol, phosphatidylcholine, cardiolipin, cholesterol, and N-palmitoyl-D-erythro-sphingosine (ceramide) was determined by liposome electrokinetic chromatography. The interactions were evaluated by calculating the retention factors and distribution constants. Atomic force microscopy measurements were carried out to confirm that the interaction mechanism was solely due to interactions between the analytes and the moving pseudostationary phase and not by interactions with a stationary lipid phase adsorbed to the fused-silica wall. The heterogeneity of the liposomes was also studied by atomic force microscopy. The liposome electrokinetic chromatography results demonstrate that there is higher interaction between the drugs and negatively charged liposome dispersion than with the commercial Intralipid dispersion.

Abstract: Fatal drug overdoses are a cause for concern all over the world. We present here a lipid-based formulation which has a strong affinity for some common illicit street drugs and can be used in vivo as a lipid ‘sink’. In this study, the in vitro interactions of nine lipophilic drugs and three lipid dispersions were determined by electrokinetic capillary chromatography and fluorescence polarization. Two lipid dispersions, zwitterionic 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine (POPC) and an anionic mixture of POPC and 1-palmitoyl-2-oleyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (POPG) were tested and compared with a commercial lipid dispersion Intralipid®, which has been successfully used for resuscitation of patients in cases of anesthetic overdoses. The interactions between dispersions and the drugs were quantified by means of retention factors and distribution constants, which makes the results highly comparable to those obtained from any other formulation of lipids. The results demonstrate a stronger interaction between the drugs and an artificial liposome dispersion than with the commercial Intralipid dispersion. The liposome dispersion composed of POPC and POPG functions as a lipid ‘sink’ for efficient entrapment of various lipophilic drugs. [ABSTRACT FROM AUTHOR]