Ionic Liquids: New Forms of Active Pharmaceutical Ingredients with Unique, Tunable Properties

This Review aims to summarize advances over the last 15 years in the development of active pharmaceutical ingredient ionic liquids (API-ILs), which make up a prospective game-changing strategy to overcome multiple problems with conventional solid-state drugs, for example, polymorphism. A critical part of the present Review is the collection of API-ILs and deep eutectic solvents (DESs) prepared to date. The Review covers rules for rational design of API-ILs and tools for API-IL formation, syntheses, and characterization. Nomenclature and ionic speciation, and the confusion that these may cause, are highlighted, particularly for speciation in both ILs and DESs of intermediate ionicity. We also highlight in vivo and in vitro pharmaceutical activity studies, with differences in pharmacokinetic/pharmacodynamic depending on ionicity of API-ILs. A brief overview is provided for the ILs used to deliver drugs, and the Review concludes with key prospects and roadblocks in translating API-ILs into pharmaceutical manufacturing.

Ionic Liquids in Agrochemistry

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In this review article, we present the latest research in the field of ionic liquids containing biologically active anions and cations, their potential application in the field of agrochemistry and agriculture. The article describes examples of the use of ionic liquids as herbicides, fungicides, antimicrobial agents, deterrents and plant growth stimulants. It also indicates the advantages and disadvantages of using ionic liquids, such as their multitasking, toxicity, thermal stability and solubility in water in comparison with commercial chemicals. Readers will find in the article the prospects for the use of ionic liquids in agriculture, as well as the high value of using ILs as multifunctional biologically active substances.

Herbicidal Ionic Liquids Containing the Acetylcholine Cation

This study presents a new group of herbicidal ionic liquids (HILs) based on a cation occurs commonly in nature-acetylcholine. The HILs were obtained with a high yield through ion exchange between acetylcholine chloride and potassium or sodium salts of selected acids with herbicidal activity. The results of the herbicidal activity measurement against common oilseed rape (Brassica napus L.) exceeded those of the commercial products. Spray solutions of the synthesized HILs revealed high surface activity and wetting properties which further manifested as higher herbicidal activity. The reduction of surface tension and low contact angles together with the specific action of acetylcholine allowed for better penetration of synthesized HILs into plant tissues. In addition, OECD 301F tests confirmed high mineralization of the HILs. The simple transformation of commercial herbicides into acetylcholine HILs proved to be a very effective method of increasing their activity, and constitutes an interesting solution to the problem of weed infestation with the use of a substance commonly found in nature.

Ionic liquids strongly affect the interaction of bacteria with magnesium oxide and silica nanoparticles

Quaternary ammonium theophylline-based ionic liquids and imidazolium-based ionic liquids, magnesium oxide and silica nanoparticles were used in order to investigate the interaction with Gram negative Escherichia coli and Gram positive Bacillus cereus. The changes of bacterial sensitivity to both nanoparticles (NPs) and ionic liquids (ILs) were examined. In order to assess the impact of ILs on the interaction of nanoparticles with bacteria, respirometric analysis, activity of dehydrogenases, peroxidase analyses as well as scanning and fluorescence microscopy examinations were conducted. The interactions of ILs with nanoparticles based on adsorption and sedimentation tests were also investigated in order to assess how the ILs affect the agglomeration of NPs. It was assumed, as the main hypothesis of the present studies, that the differences in sensitivity of bacteria to combined ILs and NPs can be observed, even if the concentration of both compounds are below the minimum inhibitory concentration (MIC). The results indicated that ILs strongly affected the sensitivity of bacteria to nanoparticles however, the changes of sensitivity depended on the surface characteristics of the nanoparticles. The presence of ILs at non-lethal concentrations caused an increase of bacterial sensitivity to MgO nanoparticles. Notably, the sensitivity of Gram positive bacteria increased significantly when ILs were present. This was an important observation because the toxicity of nanoparticles toward Gram positive bacteria is usually lower than their toxicity toward Gram negative bacteria. Using silica nanoparticles, the presence of ionic liquids caused the adsorption of bacteria onto the surface of nanoparticle agglomerates. In conclusion, two opposing effects have been observed. On the one hand, the toxicity of MgO NPs in the presence of ILs has increased. On the other hand, the presence of silica nanoparticles caused a decreased sensitivity of both types of bacteria toward ILs. Our studies indicate potentially useful processes in many environmantal protection technologies like water treatment where flocculation and disinfection are extremely needed.

Plant growth promoting N-alkyltropinium bromides enhance seed germination, biomass accumulation and photosynthesis parameters of maize (Zea mays)

N-Alkyltropinium bromides were synthesized and characterized as novel plant-growth promoting agents.

Adaptation of bacteria Escherichia coli in presence of quaternary ammonium ionic liquids

This paper presents the adaptation of Escherichia coli Gram-negative bacteria to increased concentrations of ionic liquids. Theophylline-based quaternary ammonium salts were used as an example of an ionic liquid that on the one hand includes an anion of natural origin and on the other hand is characterized by amphiphilic properties due to aliphatic chains in its structure. Theophylline-based ionic liquids can be synthesized relatively cheaply and easily and can exhibit strong antibacterial properties depending on the alkyl chain length. These compounds can also strongly affect bacterial membrane properties, including changes in electrokinetic potential as well as net surface charge. The experiments performed in this study succeeded in obtaining bacterial cultures growing at a tetradecyltrimethylammonium theophyllinate concentration three times higher than the minimum inhibition and bactericidal concentration. The adapted bacteria were characterized by intriguing changes in morphology and grew in the form of almost one-millimeter spheres in a liquid medium. It was shown that cultivation of adapted bacteria with tetradecyltrimethylammonium theophyllinate resulted in changes in the lipid membrane composition and protein patterns of the bacterial lysates, depending on the ionic liquid concentration. This study also revealed that such bacterial adaptation can increase sensitivity to antibiotics by affecting membrane properties like ionophores. These results can be potentially important with regard to synergistic or antagonistic action with other bactericidal compounds like antibiotics and nanoparticles.

Dicationic ionic liquids as new feeding deterrents

Abstract

In this study, new quaternary bis(ammonium) salts with alkyl-1,X-bis(dimethyldecylammonium) cation and saccharinate, acesulfamate, lactate and pyroglutamate anions were synthesized and characterized by ¹H and ¹³C NMR spectroscopy. Thermal gravimetric and differential scanning calorimetry analyses confirmed that all salts were thermally stable and the majority of them exhibited melting points below 100 °C. The physicochemical properties (viscosity, density, refractive index values, and solubility) of the obtained salts were determined for three compounds with lactate anions. All the tested salts have suitable properties which, in practical application, will reduce the losses caused by the most important storage insects. Most of the synthesized ionic liquids had comparable or better deterrent activity than azadirachtin—an alkaloid known as the most active antifeedant.

Graphical abstract

Electronic supplementary material

The online version of this article (10.1007/s11696-018-0495-6) contains supplementary material, which is available to authorized users.

Ammonium bio-ionic liquids based on camelina oil as potential novel agrochemicals

Third generation bio-ionic liquids (bio-ILs) were synthesized based on cheap and increasingly available camelina oil.

Biological Activity of Ionic Liquids and Their Application in Pharmaceutics and Medicine

Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in the form of ionic liquid species. The main aim of this Review is to attract a broad audience of chemical, biological, and medical scientists to study advantages of ionic liquid pharmaceutics. Overall, the discussed data highlight the importance of the research direction defined as "Ioliomics", studies of ions in liquids in modern chemistry, biology, and medicine.

Different antibacterial activity of novel theophylline-based ionic liquids - Growth kinetic and cytotoxicity studies

The aim of this study was to investigate novel theophylline-based ionic liquids and their cytotoxic effects towards model Gram-positive and Gram-negative bacteria (Bacillus cereus and Escherichia coli, respectively). Growth kinetics, respiratory rates and dehydrogenase activities were studied in the presence of ionic liquids at concentrations ranging from 10 to 1000mg/L. Additionally, the influence of ionic liquids on bacterial cells associated with specific interactions based on the structure of cell wall was evaluated. This effect was assessed by viability tests and scanning electron microscope observations. The obtained results confirmed that ionic liquids exhibit different levels of toxicity in relation to Gram-positive and Gram-negative bacteria. Those effects are associated with the chemical structure of the cationic species of the ionic liquids and their critical micelle concentration value. It was established that the presence of an alkyl or allyl group increased the toxicity, whereas the presence of an aryl group in the cation decreased the toxic effect of ILs. Results presented in this study also revealed unexpected effects of self-aggregation of E. coli cells. Overall, it was established that the studied ILs exhibited higher toxicity towards Gram-positive bacteria due to different interactions between the ILs and the cell membranes. These findings may be of importance for the design of ILs with targeted antimicrobial properties.

Pyrrolidinium herbicidal ionic liquids

In this work, sixteen new pyrrolidinium herbicidal ionic liquids (HILs) with phenoxycarboxylate anions were synthesized and characterized.

Bis(ammonium) ionic liquids with herbicidal anions

The method of synthesis of the novel bis(ammonium) herbicidal ionic liquids with the cation containing two quaternary nitrogen atoms was described.

Ammonium ionic liquids with anions of natural origin

Ammonium ionic liquids with anions of natural origin are biodegradable agents with antifeedant and anti-microbial activity.