Lanthanide-Based Organic Salts: Synthesis, Characterization, and Cytotoxicity Studies

The formulation of magnetic ionic liquids (MILs) or organic salts based on lanthanides as anions has been explored. In this work, a set of choline-family-based salts, and two other, different cation families, were combined with Gadolinium(III) and Terbium(III) anions. Synthetic methodologies were previously optimized, and all organic salts were obtained as solids with melting temperatures higher than 100 °C. The magnetic moments obtained for the Gd(III) salts were, as expected, smaller than those obtained for the Tb(III)-based compounds. The values for Gd(III) and Tb(III) magnetic salts are in the range of 6.55-7.30 MB and 8.22-9.34 MB, respectively. It is important to note a correlation between the magnetic moments obtained for lanthanides, and the structural features of the cation. The cytotoxicity of lanthanide-based salts was also evaluated using 3T3, 293T, Caco2, and HepG2 cells, and it was revealed that most of the prepared compounds are not toxic.

Beneficial and detrimental effects of choline chloride-oxalic acid deep eutectic solvent on biogas production

Deep eutectic solvents (DES), a new class of alternative solvents, have recently been used in the pre-treatment of lignocellulosic biomass. Due to the ability to dissolve phenolic compounds, they have been efficiently applied as delignification agents. However, to extend DES application to bioprocesses, such as Anaerobic Digestion (AD), their toxicity to microbial consortia must be evaluated. In this work, an effective delignifying DES, composed of choline chloride (ChCl) and oxalic acid (OA) (1:1) was prepared and its effect evaluated, for the first time, in biogas production. Results show that the presence of DES had both beneficial and detrimental effects on the anaerobic consortium, depending on its concentration. In the concentration range of 0.3-12.5 g/L, the presence of DES led to a lag-phase of 1 to 8 d as the DES concentration increased. However, after the lag-phase has been surpassed, DES up to a concentration of 12.5 g/L improved the biogas production, reaching an accumulated biogas volume three times higher than the control assay for the concentration of 12.5 g/L. For the highest DES concentrations (19.8-78.1 g/L), the biogas production was inhibited. The assays performed with DES components alone have indicated that OA at 3.2 g/L was the main responsible for the inhibition of biogas production (50% less biogas produced than the control). ChCl at 4.9 g/L has not presented a lag-phase and produced an accumulated biogas volume like the control assay (1200 mL for 30 d incubation). This work points out that ChCl:OA DES may be used in the delignification of biomass further submitted to AD, provided the inhibitory concentrations of OA are not achieved.

Mesoporous silica nanoparticles with manganese and lanthanide salts: synthesis, characterization and cytotoxicity studies

Several organic salts based on the combination of two different choline derivative cations and MnCl3-, GdCl4- and TbCl4- as anions were immobilized in mesoporous silica nanoparticles (MSNs) by a two-step synthetic method. Firstly, MSNs were functionalized with choline derivative cations with chloride anions and then the metals were incorporated by the reaction of the chloride with the respective metal chloride salts. These nanomaterials were fully characterized by different characterization techniques such as 1H-NMR, FT-IR, elemental analysis, TEM, TGA, N2 adsorption, XRD and DLS. These characterization data were important to confirm the successful functionalization of the nanomaterials and to access their textural properties and colloidal stability. The final materials were also characterized by ICP-MS that indicated the metal contents. The cytotoxicity profile was evaluated in four different cell lines (3T3, 293T, HepG2 and Caco-2), which shows some relevant differences between the metal organic salts and their immobilized analogues.

Vapor Pressure Assessment of Sulfolane-Based Eutectic Solvents: Experimental, PC-SAFT, and Molecular Dynamics

Since their discovery, deep eutectic solvents (DES) have been explored in multiple applications. However, the complete physicochemical characterization is still nonexistent for many of the proposed and used DES. In particular, vapor pressure, which is a crucial property for the application of DES as solvents, is very rarely available. In this work, the measurement of the total and partial pressures of two sulfolane-based DES, tetrabutylammonium bromide:sulfolane and tetrabutylphosphonium bromide:sulfolane, in several proportions, from 40 to 100 °C and atmospheric pressure, was performed using headspace gas chromatography mass spectrometry, HS-GC-MS. A large decrease on the total pressure was recorded which, together with the finding that total pressures showed negative deviations from Raoult's law, is indicative of the favorable, strong interactions between the two components within the DES. Additionally, the study of vapor pressure change with DES molar composition was carried out, and surprisingly, the existence of inflection points in the pressure curve was observed. Experimental results were modeled using the PC-SAFT equation of state, and in addition, MD simulations were performed to provide a molecular understanding of the pressure data. Considering the different results and insights obtained from the used strategies, it can be concluded that both DES systems have especially strong interactions between salt and sulfolane, at high sulfolane content, due to the different structural rearrangement of the liquid state.

Thin Porous Poly(ionic liquid) Coatings for Enhanced Headspace Solid Phase Microextraction

In this contribution, thin poly(ionic liquid) (PIL) coatings with a well-defined pore structure built up from interpolyelectrolyte complexation between a PIL and poly(acrylic acid) (PAA) were successfully used for enhanced solid phase microextraction (SPME). The introduction of porosity with tunable polarity through the highly versatile PIL chemistry clearly boosts the potential of SPME in the detection of compounds at rather low concentrations. This work will inspire researchers to further explore the potential of porous poly(ionic liquid) materials in sensing and separation applications.

Antimicrobial Activities of Highly Bioavailable Organic Salts and Ionic Liquids from Fluoroquinolones

As the development of novel antibiotics has been at a halt for several decades, chemically enhancing existing drugs is a very promising approach to drug development. Herein, we report the preparation of twelve organic salts and ionic liquids (OSILs) from ciprofloxacin and norfloxacin as anions with enhanced antimicrobial activity. Each one of the fluoroquinolones (FQs) was combined with six different organic hydroxide cations in 93-100% yield through a buffer-assisted neutralization methodology. Six of those were isomorphous salts while the remaining six were ionic liquids, with four of them being room temperature ionic liquids. The prepared compounds were not toxic to healthy cell lines and displayed between 47- and 1416-fold more solubility in water at 25 and 37 °C than the original drugs, with the exception of the ones containing the cetylpyridinium cation. In general, the antimicrobial activity against Klebsiella pneumoniae was particularly enhanced for the ciprofloxacin-based OSILs, with up to ca. 20-fold decreases of the inhibitory concentrations in relation to the parent drug, while activity against Staphylococcus aureus and the commensal Bacillus subtilis strain was often reduced. Depending on the cation-drug combination, broad-spectrum or strain-specific antibiotic salts were achieved, potentially leading to the future development of highly bioavailable and safe antimicrobial ionic formulations.

Dual nanofibrillar-based bio-sorbent films composed of nanocellulose and lysozyme nanofibrils for mercury removal from spring waters

The present study explores the preparation of dual nanofibrillar-based bio-sorbent films composed of cellulose nanofibrils (CNFs) and lysozyme nanofibrils (LNFs) for application in the removal of Hg(II) from aqueous solutions. The free-standing films were fabricated via simple vacuum filtration of water suspensions of CNFs and LNFs and disclose good mechanical and thermal properties. The Hg(II) removal efficiency was evaluated by atomic fluorescence spectroscopy in ultra-pure and natural spring waters contaminated with environmental realistic levels of mercury (50 μg L^-1). The removal efficiency is pH-dependent reaching a maximum of 99 % after 24 h at a pH value close to the isoelectric point of the protein. Under the experimental conditions, the sorption kinetics are well described by the pseudo-second-order and Elovich models, suggesting a chemisorption mechanism. These results demonstrate the ability of the dual nanofibrillar-based films to remove Hg(II) from water samples reaching a residual concentration lower than the guideline value for water intended for human consumption (1 μg L^-1). Therefore, the CNFs/LNFs bio-sorbents might be a solution to treat low-concentrated mercury-contaminated waters.

Tuning the miscibility of water in imide-based ionic liquids

Experimental and theoretical study on mixtures of water with ionic liquids exhibiting unusual temperature concentration phase diagrams.

Influence of Betaine- and Choline-based Eutectic Solvents on Lipase Activity

Background:

Eutectic solvents are a mixture of two compounds which possess a lower melting temperature than the parent compounds, using quaternary ammonium salts, such as choline chloride and betaine hydrochloride and organic acids, polyols and amides as hydrogen bond donors. These solvents can be an alternative as non-aqueous media for enzymatic reactions, mainly using lipases.

Objective:

The objective of this work is to evaluate enzymatic activity and stability of commercial lipases, immobilized or at free form (Thermomyces lanuginosus: Lipozyme TL IM, iTL and Lipolase 100 L, fTL; Candida antarctica: Novozym 435, iCALB; Novozym 735, iCALA and Novozym CALB L, fCALB); and a phospholipase (Lecitase Ultra), in the presence of eutectic solvents (choline chloride ChCl:urea, ChCl:glycerol, betaine hydrochloride (BeHCl):urea and BeHCl: glycerol.

Methods:

Initially, lipases were maintained for 2 hours in solutions of choline and betaine-based eutectic solvents (1 to 20% m/m) at 25ºC compared with water for relative enzymatic activity. Using the solvent that best promoted lipase activity, some parameters were evaluated such as the molar ratio between quaternary ammonium salts and urea, stocking temperature and kinetics.

Results and Conclusion:

These eutectic solvents enable, mainly with immobilized lipases, 25 to 125 times more activity than water at 25ºC and 2h, and even after 24h, lipase iTLL was still 40 times more active in the presence of ChCl:Urea 1:3. Lipase iCALB showed great thermostability 47 times higher at 55ºC, almost double relative activity at 25ºC in the presence of BetHCl:Urea 1:4.

Quest for Green-Solvent Design: From Hydrophilic to Hydrophobic (Deep) Eutectic Solvents

Deep eutectic solvents (DESs) consist of a mixture of two or more solid components, which gives rise to a lower melting point compared to the starting materials. Until recently only hydrophilic DESs were available, and despite their revolutionary role in the alternative-solvents field, important issues in chemistry, and chemical engineering (such as water-related problems and the replacement of toxic volatile organic compounds) could not be tackled. Hydrophobic (deep)-here in parenthesis due to the different depths of the eutectic melting points-eutectic solvents are a subclass of DESs where both components are hydrophobic. The low toxicity, high biodegradability, and straightforward preparation without further purification steps of naturally occurring low-cost compounds are among the key advantages. Although research on hydrophobic DESs is scarce (the first report was only published in 2015), some interesting features and applications have been reported and deserve to be evaluated and comparisons established. This Minireview is divided into two parts: The first part provides a brief general introduction to DESs and the second part discusses the nomenclature using solid-liquid phase diagram analysis, chemical stability, thermophysical properties comparison, and finally the most important emerging fields of application.

Quest for Green-Solvent Design: From Hydrophilic to Hydrophobic (Deep) Eutectic Solvents

Deep eutectic solvents (DESs) consist of a mixture of two or more solid components, which gives rise to a lower melting point compared to the starting materials. Until recently only hydrophilic DESs were available, and despite their revolutionary role in the alternative-solvents field, important issues in chemistry, and chemical engineering (such as water-related problems and the replacement of toxic volatile organic compounds) could not be tackled. Hydrophobic (deep)-here in parenthesis due to the different depths of the eutectic melting points-eutectic solvents are a subclass of DESs where both components are hydrophobic. The low toxicity, high biodegradability, and straightforward preparation without further purification steps of naturally occurring low-cost compounds are among the key advantages. Although research on hydrophobic DESs is scarce (the first report was only published in 2015), some interesting features and applications have been reported and deserve to be evaluated and comparisons established. This Minireview is divided into two parts: The first part provides a brief general introduction to DESs and the second part discusses the nomenclature using solid-liquid phase diagram analysis, chemical stability, thermophysical properties comparison, and finally the most important emerging fields of application.

Neat ionic liquids versus ionic liquid mixtures: a combination of experimental data and molecular simulation

Simple mixtures of ionic liquids (IL–IL mixtures) can become a promising approach for the substitution of task-specific ILs.

Towards Biohydrogen Separation Using Poly(Ionic Liquid)/Ionic Liquid Composite Membranes

Considering the high potential of hydrogen (H₂) as a clean energy carrier, the implementation of high performance and cost-effective biohydrogen (bioH₂) purification techniques is of vital importance, particularly in fuel cell applications. As membrane technology is a potentially energy-saving solution to obtain high-quality biohydrogen, the most promising poly(ionic liquid) (PIL)–ionic liquid (IL) composite membranes that had previously been studied by our group for CO₂/N₂ separation, containing pyrrolidinium-based PILs with fluorinated or cyano-functionalized anions, were chosen as the starting point to explore the potential of PIL–IL membranes for CO₂/H₂ separation. The CO₂ and H₂ permeation properties at the typical conditions of biohydrogen production (T = 308 K and 100 kPa of feed pressure) were measured and discussed. PIL–IL composites prepared with the [C(CN)₃]⁻ anion showed higher CO₂/H₂ selectivity than those containing the [NTf₂]⁻ anion. All the membranes revealed CO₂/H₂ separation performances above the upper bound for this specific separation, highlighting the composite incorporating 60 wt % of [C₂mim][C(CN)₃] IL.

Supramolecular hydrogel based on a sodium deep eutectic solvent

Supramolecular hydrogel based on a metal containing deep eutectic solvent (DES) is presented here for the first time.

Improved Monitoring of Aqueous Samples by the Concentration of Active Pharmaceutical Ingredients using Ionic-Liquid-based Systems

Fluoroquinolones (FQs) and Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are two classes of Active Pharmaceutical Ingredients (APIs), widespreadly used in human healthcare and as veterinary drugs, and that have been found throughout the water cycle in the past years. These two classes of APIs are commonly present in aqueous streams in concentrations ranging from ng.L-1 to µg.L-1. Despite such low concentrations, these contaminants tend to bioaccumulate, leading to serious environmental and health issues after chronic exposure. The low concentrations of FQs and NSAIDs in aqueous media also render their difficult identification and quantification, wich may result in an unefficient evaluation of their environmental impact and persistence. Therefore, the development of alternative pre-treatment techniques for their extraction and concentration from aqueous samples is a crucial requirement. In this work, liquid-liquid systems, namely ionic-liquid-based aqueous biphasic systems (IL-based ABS), were tested as simultaneous extraction and concentration platforms of FQs and NSAIDs. ABS composed of imidazolium-, ammonium- and phosphonium-based ILs and a citrate-based salt (C6H5K3O7) were evaluated for the single-step extraction and concentration of three FQs (ciprofloxacin, enrofloxacin and norfloxacin) and three NSAIDs (diclofenac, naproxen and ketoprofen) from aqueous samples. Outstanding one-step extraction efficiencies of APIs close to 100% were obtained. Furthermore, concentration factors of both FQs and NSAIDs were optimized by an appropriate manipulation of the phase-forming components compositions to tailor the volumes of the coexisting phases. Concentration factors of 1000-fold of both FQS and NSAIDs were obtained in a single-step, without reaching the saturation of the IL-rich phase. The concentration of APIs up to the mg.L-1 allowed their easy and straightforward identification and quantification by High-Performance Liquid Chromatography (HPLC) coupled to an UV detector, as shown either with model aqueous samples or real wastewater effluent samples.

Removal of Non-Steroidal Anti-Inflammatory Drugs from Aqueous Environments with Reusable Ionic-Liquid-based Systems

In the current era of human life, we have been facing an increased consumption of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs). Nevertheless, NSAIDs are not completely metabolized by humans and are further excreted into domestical effluents. Several studies have been showing that a wide variety of pharmaceuticals are present in water effluents and are thus a matter of serious concern in the public health. Although treatment plants use sophisticated technologies for pollutants/contaminants removal, none of these processes was particularly designed for NSAIDs. In this perspective, this work addresses the use of a liquid-liquid extraction approach, employing ionic liquids (ILs), for the removal of NSAIDs from aqueous media. In particular, aqueous biphasic systems (ABS) composed of ILs and aluminium-based salts, which are already used in water treatment plants, were tested for the removal of diclofenac, ibuprofen, naproxen and ketoprofen. With these systems, extraction efficiencies of NSAIDs up to 100% were obtained in a single-step. The recovery of NSAIDs from the IL medium and the recyclability of the IL-rich phase were then ascertained to guarantee the development of a more sustainable and cost-effective strategy. Based on the remarkable increase in the solubility of NSAIDs in the IL-rich phase (from a 300- to a 4100-fold when compared with pure water), water was then studied as an effective anti-solvent, and where single-step recovery percentages of NSAIDs from the IL-rich phase up to 91% were obtained. After the "cleaning" of the IL-rich phase by the induced precipitation of NSAIDs, the phase-forming components were recovered and reused in four consecutive cycles, with no detected losses on both the extraction efficiency and recovery of NSAIDs by induced precipitation. Finally, an integrated process is here proposed, which comprises the (i) removal of NSAIDs from aqueous media, (ii) the cleaning of the IL-rich phase by the recovery of NSAIDs by induced precipitation, and (iii) the phase-forming components recycling and reuse, aiming at unlocking new doors for alternative treatment strategies of aqueous environments.

Highly water soluble room temperature superionic liquids of APIs

Herein a straightforward approach for the enhancement of the water solubility of common antibiotic and NSAID active pharmaceutical ingredients (APIs) is presented.

Ionic liquids with anions based on fluorosulfonyl derivatives: from asymmetrical substitutions to a consistent force field model

Herein, seven anions including four imide-based and two sulfonate anions are considered and compared.

Exploring the effect of fluorinated anions on the CO2/N2 separation of supported ionic liquid membranes

The CO₂ and N₂ permeation properties of ionic liquids (ILs) based on a common imidazolium cation and different fluorinated anions were measured using supported ionic liquid membranes (SILMs).

Aging of Rigid Polyurethane Foams: Thermal Conductivity of N2 and Cyclopentane Gas Mixtures

The thermal conductivity of three mixtures of nitrogen and cyclopentane is measured using a transient hot wire method, at temperatures between 315.14 and 395.89 K, and pressures up to 0.53 MPa. These mixtures are important in the evaluation of the evolution of the thermal insulation capacity of closed-cell polyurethane foams considering their aging during the respective applications’ total life time. The experimental thermal conductivity data are correlated with the Wassiljewa mixing rules as modified by Mason and Saxena, and predicted using extended corresponding states theory (ECST), with an average absolute deviation of 1.1 and 8.9%, respectively. The increase of the nitrogen fraction in cyclopentane-nitrogen mixtures leads to higher thermal conductivity values than has been predicted by ECST using only pure component thermal conductivity data for all measurements.

Improved extraction of fluoroquinolones with recyclable ionic-liquid-based aqueous biphasic systems

In the past few years, the improvement of advanced analytical tools allowed to confirm the presence of trace amounts of metabolized and unchanged active pharmaceutical ingredients (APIs) in wastewater treatment plants (WWTPs) as well as in freshwater surfaces. It is known that the continuous contact with APIs, even at very low concentrations (ng L^-1-μg L^-1), leads to serious human health problems. In this context, this work shows the feasibility of using ionic-liquid-based aqueous biphasic systems (IL-based ABS) in the extraction of quinolones present in aqueous media. In particular, ABS composed of imidazolium- and phosphonium-based ILs and aluminium-based salts (already used in water treatment plants) were evaluated in one-step extractions of six fluoroquinolones (FQs), namely ciprofloxacin, enrofloxacin, moxifloxacin, norfloxacin, ofloxacin and sarafloxacin, and extraction efficiencies up to 98% were obtained. Despite the large interest devoted to IL-based ABS as extractive systems of outstanding performance, their recyclability/reusability has seldomly been studied. An efficient extraction/cleaning process of the IL-rich phase is here proposed by FQs induced precipitation. The recycling of the IL and its further reuse without losses in the ABS extractive performance for FQs were established, as confirmed by the four consecutive removal/extraction cycles evaluated. This novel recycling strategy supports IL-based ABS as sustainable and cost-efficient extraction platforms.

Ionic liquid-based materials: a platform to design engineered CO2 separation membranes

This review provides a judicious assessment of the CO₂ separation efficiency of membranes using ionic liquid-based materials and highlights breakthroughs and key challenges in this field.

Turning into poly(ionic liquid)s as a tool for polyimide modification: synthesis, characterization and CO2 separation properties

A synthetic method for the transformation of polyimides into poly(ionic liquid)s with improved properties is suggested.

Mixtures of the 1-ethyl-3-methylimidazolium acetate ionic liquid with different inorganic salts: insights into their interactions

The interactions between the ionic liquid 1-ethyl-3-methylimidazolim acetate and [NH₄]-based inorganic salts is stronger than those between the IL and Na-based.

Antitumor Activity of Ionic Liquids Based on Ampicillin

Significant antiproliferative effects against various tumor cell lines were observed with novel ampicillin salts as ionic liquids. The combination of anionic ampicillin with appropriate ammonium, imidazolium, phosphonium, and pyridinium cations yielded active pharmaceutical ingredient ionic liquids (API-ILs) that show potent antiproliferative activities against five different human cancer cell lines: T47D (breast), PC3 (prostate), HepG2 (liver), MG63 (osteosarcoma), and RKO (colon). Some API-ILs showed IC50 values between 5 and 42 nM, activities that stand in dramatic contrast to the negligible cytotoxic activity level shown by the ampicillin sodium salt. Moreover, very low cytotoxicity against two primary cell lines-skin (SF) and gingival fibroblasts (GF)-indicates that the majority of these API-ILs are nontoxic to normal human cell lines. The most promising combination of antitumor activity and low toxicity toward healthy cells was observed for the 1-hydroxyethyl-3-methylimidazolium-ampicillin pair ([C2 OHMIM][Amp]), making this the most suitable lead API-IL for future studies.

Aggregation behavior and total miscibility of fluorinated ionic liquids in water

In this work, novel and nontoxic fluorinated ionic liquids (FILs) that are totally miscible in water and could be used in biological applications, where fluorocarbon compounds present a handicap because their aqueous solubility (water and biological fluids) is in most cases too low, have been investigated. The self-aggregation behavior of perfluorosulfonate-functionalized ionic liquids in aqueous solutions has been characterized using conductometric titration, isothermal titration calorimetry (ITC), surface tension measurements, dynamic light scattering (DLS), viscosity and density measurements, and transmission electron microscopy (TEM). Aggregation and interfacial parameters have been computed by conductimetry, calorimetry, and surface tension measurements in order to study various thermodynamic and surface properties that demonstrate that the aggregation process is entropy-driven and that the aggregation process is less spontaneous than the adsorption process. The novel perfluorosulfonate-functionalized ILs studied in this work show improved surface activity and aggregation behavior, forming distinct self-assembled structures.

Poly(ionic liquid)s as phase splitting promoters in aqueous biphasic systems

The ability of hydrophilic pyrrolidinium-based PILs to promote phase splitting in aqueous solutions of K₃PO₄ is disclosed in this work for the first time.

Ionic liquids in pharmaceutical applications

In the past several years, ionic liquids (ILs) have been at the cutting edge of the most promising science and technology. ILs not only have found applications in classical areas of knowledge but also are important candidates to solve classical problems within several societal challenges, such as clean and efficient energy, through the development of a broad swath of energy technologies, such as advanced batteries, dye-sensitized solar cells, double-layer capacitors, actuators, fuel cells, thermo-cells, and water splitting, essentially related to highly efficient carbon capture and storage technologies and resource efficiency to date. This review focuses on the application of IL methodologies to solve critical pharmaceutical problems, in particular, the low solubility and thus bioavailability of pharmaceutical compounds and the presence of polymorphs, which severely hamper the efficacy of important commercially available drugs. The development of strategies to use ILs as carriers of pharmaceutical active compounds is an extremely promising and wide avenue. Further, the synthesis of liquid salts through the discerning combination of cations and anions with several distinct pharmaceutical roles provides answers to some of today's pharmaceutical industrial challenges.

The impact of ionic liquid fluorinated moieties on their thermophysical properties and aqueous phase behaviour

In this work, we demonstrate that the presence of fluorinated alkyl chains in Ionic Liquids (ILs) is highly relevant in terms of their thermophysical properties and aqueous phase behaviour. We have measured and compared the density and viscosity of pure 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate, [C2C1im][FAP], with that of pure 1-ethyl-3-methylimidazolium hexafluorophosphate, [C2C1im][PF6], at atmospheric pressure and in the (288.15 to 363.15) K temperature range. The results show that the density of [C2C1im][PF6] is lower than that of [C2C1im][FAP], while the viscosity data reveal the opposite trend. The fluid phase behaviour of aqueous solutions of the two ILs was also evaluated under the same conditions and it was found that the mutual solubilities of [C2C1im][FAP] and water are substantially lower than those verified with [C2C1im][PF6]. The experimental data were lastly interpreted at a molecular level using Molecular Dynamics (MD) simulation results revealing that the interactions between the IL ions and the water molecules are mainly achieved via the six fluorine atoms of [PF6](-) and the three analogues in [FAP](-). The loss of three interaction centres when replacing [PF6](-) by [FAP](-), coupled with the bulkiness and relative inertness of the three perfluoroethyl groups, reduces its mutual solubility with water and also contributes to a lower viscosity displayed by the pure [FAP]-based IL as compared to that of the [PF6]-based compound.

Novel organic salts based on fluoroquinolone drugs: synthesis, bioavailability and toxicological profiles

In order to overcome the problems associated with low water solubility, and consequently low bioavailability of active pharmaceutical ingredients (APIs), novel organic salts containing fluoroquinolones (e.g. ciprofloxacin and norfloxacin) were prepared, using an optimized synthetic procedure based on direct protonation, with different biocompatible counter ions such as mesylate, gluconate and glycolate. All the prepared organic salts were characterized by spectroscopic techniques, mass spectrometry and thermal analysis. Solubility studies in water and simulated biological fluids at 25°C and 37°C were also performed. Additionally, octanol-water and phospholipid-water partition coefficients were measured at 25°C. The cytotoxicity and anti-inflammatory efficacy using an human cell model of intestinal epithelia (Caco-2 cells) were also evaluated and compared to those of the parent APIs. The adequate selection of the biocompatible anions allows the tuning of important physical, thermal and toxicological properties.