Ionic liquids containing ketoconazole improving topical treatment of T. Interdigitale infection by synergistic action

Synthesis, Characterisation, and In Vitro Evaluation of Biocompatibility, Antibacterial and Antitumor Activity of Imidazolium Ionic Liquids

In recent decades, ionic liquids (ILs) have garnered research interest for their noteworthy properties, such as thermal stability, low or no flammability, and negligible vapour pressure. Moreover, their tunability offers limitless opportunities to design ILs with properties suitable for applications in many industrial fields. This study aims to synthetise two series of methylimidazolium ILs bearing long alkyl chain in their cations (C9, C10, C12, C14, C16, C18, C20) and with tetrafluoroborate (BF4) and the 1,3-dimethyl-5-sulfoisophthalate (DMSIP) as counter ions. The ILs were characterised using 1H-NMR and MALDI-TOF, and their thermal behaviour was investigated through DSC and TGA. Additionally, the antimicrobial, anticancer, and cytotoxic activities of the ILs were analysed. Moreover, the most promising ILs were incorporated at different concentrations (0.5, 1, 5 wt%) into polyvinyl chloride (PVC) by solvent casting to obtain antimicrobial blend films. The thermal properties and stability of the resulting PVC/IL films, along with their hydrophobicity/hydrophilicity, IL surface distribution, and release, were studied using DSC and TGA, contact angle (CA), SEM, and UV-vis spectrometry, respectively. Furthermore, the antimicrobial and cytotoxic properties of blends were analysed. The in vitro results demonstrated that the antimicrobial and antitumor activities of pure ILs against t Listeria monocytogenes, Escherichia coli, Pseudomonas fluorescens strains, and the breast cancer cell line (MCF7), respectively, were mainly dependent on their structure. These activities were higher in the series containing the BF4 anion and increased with the increase in the methylimidazolium cation alkyl chain length. However, the elongation of the alkyl chain beyond C16 induced a decrease in antimicrobial activity, indicating a cut-off effect. A similar trend was also observed in terms of in vitro biocompatibility. The loading of both the series of ILs into the PVC matrix did not affect the thermal stability of PVC blend films. However, their Tonset decreased with increased IL concentration and alkyl chain length. Similarly, both the series of PVC/IL films became more hydrophilic with increasing IL concentration and alkyl chain. The loading of ILs at 5% concentration led to considerable IL accumulation on the blend film surfaces (as observed in SEM images) and, subsequently, their higher release. The biocompatibility assessment with healthy human dermal fibroblast (HDF) cells and the investigation of antitumoral properties unveiled promising pharmacological characteristics. These findings provide strong support for the potential utilisation of ILs in biomedical applications, especially in the context of cancer therapy and as antibacterial agents to address the challenge of antibiotic resistance. Furthermore, the unique properties of the PVC/IL films make them versatile materials for advancing healthcare technologies, from drug delivery to tissue engineering and antimicrobial coatings to diagnostic devices.

Ionic liquids as the effective technology for enhancing transdermal drug delivery: Design principles, roles, mechanisms, and future challenges

Ionic liquids (ILs) have been proven to be an effective technology for enhancing drug transdermal absorption. However, due to the unique structural components of ILs, the design of efficient ILs and elucidation of action mechanisms remain to be explored. In this review, basic design principles of ideal ILs for transdermal drug delivery system (TDDS) are discussed considering melting point, skin permeability, and toxicity, which depend on the molar ratios, types, functional groups of ions and inter-ionic interactions. Secondly, the contributions of ILs to the development of TDDS through different roles are described: as novel skin penetration enhancers for enhancing transdermal absorption of drugs; as novel solvents for improving the solubility of drugs in carriers; as novel active pharmaceutical ingredients (API-ILs) for regulating skin permeability, solubility, release, and pharmacokinetic behaviors of drugs; and as novel polymers for the development of smart medical materials. Moreover, diverse action mechanisms, mainly including the interactions among ILs, drugs, polymers, and skin components, are summarized. Finally, future challenges related to ILs are discussed, including underlying quantitative structure-activity relationships, complex interaction forces between anions, drugs, polymers and skin microenvironment, long-term stability, and in vivo safety issues. In summary, this article will promote the development of TDDS based on ILs.

Mechanisms of antifungal resistance and developments in alternative strategies to combat Candida albicans infection

Candida albicans is a commensal fungus that infects the humans and becomes an opportunistic pathogen particularly in immuno-compromised patients. Among the Candida genus, yeast C. albicans is the most frequently incriminated species and is responsible for nearly 50-90% of human candidiasis, with vulvovaginal candidiasis alone, affecting about 75% of the women worldwide. One of the significant virulence traits in C. albicans is its tendency to alternate between the yeast and hyphae morphotypes, accounting for the development of multi-drug resistance in them. Thus, a thorough comprehension of the decision points and genes controlling this transition is necessary, to understand the pathogenicity of this, naturally occurring, pernicious fungus. Additionally, the formation of C. albicans biofilm is yet another pathogenesis trait and a paramount cause of invasive candidiasis. Since 1980 and in 90 s, wide spread use of immune-suppressing therapies and over prescription of fluconazole, a drug used to treat chronic fungal infections, triggered the emergence of novel anti-fungal drug development. Thus, this review thoroughly elucidates the diseases associated with C. albicans infection as well as the anti-fungal resistance mechanism associated with them and identifies the emerging therapeutic agents, along with a rigorous discussion regarding the future strategies that can possibly be adopted for the cure of this deleterious pathogen.

Drug-Facilitated Crystallization of Spray-Dried CD-MOFs with Tunable Morphology, Porosity, And Dissolution Profile

Metal-organic frameworks (MOFs) with versatile functionalities have applications in environmental science, sensor separation, catalysis, and drug delivery. In particular, MOFs used in drug delivery should be biodegradable and easy to control. In this study, spray-dried cyclodextrin-based MOFs (CD-MOFs) with tunable crystallinity, porosity, and dissolution properties were fabricated. The spray-drying precursor properties, such as ethanol volume ratio, incubation time, and precursor concentration, were optimized for controlled crystallization. On the basis of the morphology, X-ray diffraction peak intensity, and specific surface areas of the spray-dried CD-MOF products, they were categorized as amorphous, partially crystalline, and highly crystalline. An active pharmaceutical ingredient ketoconazole (KCZ) was introduced into the precursor to prepare KCZ-containing CD-MOFs. The surface areas of these products were greater by 3-fold (292 m2/g) than that of the plain CD-MOF (94.1 m2/g) prepared using the same parameters. The presence of KCZ in the hydrophobic cavity between the two γ-CD molecules was correlated to the CD-MOF crystal growth. Additionally, CD-MOF particles exhibited different dissolution behaviors on the basis of the position of KCZ in the MOF. These spray-dried CD-MOFs with tunable morphology, specific surface area, and dissolution could have potential applications in various fields.

Deep Eutectic Systems as Novel Vehicles for Assisting Drug Transdermal Delivery

In recent years, deep eutectic systems (DES) emerged as novel vehicles for facilitating the transdermal delivery of various drugs, including polysaccharides, proteins, insulin, vaccine, nanoparticles, and herb extracts. The objective of this study is to conduct a comprehensive review of the application of DES to transdermal drug delivery, based on previous work and the reported references. Following a brief overview, the roles of DES in TDDS, the modes of action, as well as the structure-activity relationship of DES are discussed. Particularly, the skin permeation of active macromolecules and rigid nanoparticles, which are the defining characteristics of DES, are extensively discussed. The objective is to provide a comprehensive understanding of the current investigation and development of DES-based transdermal delivery systems, as well as a framework for the construction of novel DES-TDDS in the future.

An overview of biomedical applications of choline geranate (CAGE): a major breakthrough in drug delivery

A number of studies are on the way to advancing the field of biomedical sciences using ionic liquids (ILs) and deep eutectic solvents (DESs) in view of their unique properties and inherent tunability. These significant solvents tend to enhance the physical properties of the drug, increase their bioavailability and promote the delivery of recalcitrant drugs to the body. One such widely investigated tempting multipurpose IL/DES system is choline geranate (CAGE), which has gained significant interest due to its biocompatible and highly potent antiseptic behavior, which also facilitates its sanitizing ability to combat the coronavirus. This review focuses on total advancements in biomedical applications of CAGE. This biocompatible IL/DES has made facile the solubilization of hydrophobic and hydrophilic drugs and delivery of intractable drugs through physiological barriers by stabilizing proteins and nucleic acids. Therefore, it has been used as a transdermal, subcutaneous, and oral delivery carrier and as an antimicrobial agent to treat infectious diseases and wounds as approved by laboratory and clinical translations. Moreover, current challenges and future outlooks are also highlighted to explore them more purposefully.

The Study of Deep Eutectic Solvent Based on Choline Chloride and L-(+)-Tartaric Acid Diethyl Ester for Transdermal Delivery System

Deep eutectic solvents (DESs) based on choline chloride (C) and L-(+)-tartaric acid diethyl ester (L) were prepared and used in transdermal drug delivery system (TDDS). The internal chemistry structure including the formation and changes of hydrogen bonds of choline chloride and L-(+)-tartaric acid diethyl ester DES was characterized via attenuated total reflection Fourier transform infrared (ATR-FTIR) and ¹H nuclear magnetic resonance (¹H NMR) spectroscopy. The stoichiometric ratio of choline chloride to L-(+)-tartaric acid diethyl ester as well as water content affected the viscosity, glass transition temperature (T_g), and drug solubility of the DES. The viscosity and glass transition temperature of the DES (CL14) prepared at the ratio of 1:4 of choline chloride to L-(+)-tartaric acid diethyl ester were 1.19 Pa·s and - 44.01°C, respectively, and decreased to 0.10 Pa·s and - 55.31°C when 10% water (CL1410) was added. Taking diclofenac diethylamine (DDEA), the nonsteroidal anti-inflammatory drug as model, drug solubility was as high as 60 mg/ml and 250 mg/ml in CL14 and CL1410, respectively. The cumulative amount of DDEA was 4.63 ± 2.67 μg/cm² and 15.27 ± 4.63 μg/cm² for CL14 and CL1410, respectively, at 8 h. The mechanism of percutaneous permeability by the DES may be the disturbance of stratum corneum (SC) lipids as well as changes in the protein conformations. CL14 and CL1410 were also verified as low-cytotoxic and nonirritant. Therefore, the DESs studied are promising to be used in drug solubilization enhancement and transdermal drug delivery system.

Deep eutectic solvents: Recent advances in fabrication approaches and pharmaceutical applications

Deep eutectic solvents (DESs) have received increasing attention in the past decade owing to their distinguished properties including biocompatibility, tunability, thermal and chemical stability. Particularly, DESs have joined forces in pharmaceutical industry, not only to efficiently separate actives from natural products, but also to dramatically increase solubility and permeability of drugs, both are critical for the drug absorption and efficacy. As a result, lately DESs have been extensively and practically adopted as versatile drug delivery systems for different routes such as nasal, transdermal and oral administration with enhanced bioavailability. This review summarizes the emerging progress of DESs by introducing applied fabrication approaches with advantages and limitations thereof, and by highlighting the pharmaceutical applications of DESs.

Ionic Liquids Assisted Topical Drug Delivery for Permeation Enhancement: Formulation Strategies, Biomedical Applications, and Toxicological Perspective

Topical drug delivery provides several benefits over other conventional routes by providing localizing therapeutic effects and also avoids the gastrointestinal tract circumventing the first-pass metabolism and enzymatic drug degradation. Being painless, the topical route also prevents the difficulties linked with the parenteral route. However, there are limitations to the current topical systems which necessitate the need for further research to find functional excipients to overcome these limitations. This review deals in depth with the ionic liquids concerning their physicochemical properties and applicability as well as their role in the arena of topical drug delivery in permeation enhancement, bioavailability enhancement of the drugs by solvation, and drug moiety modification. The review gives a detailed insight into the recent literature on ionic liquid-based topical formulations like ionic liquid-based emulsions, active pharmaceutical ingredient-ionic liquids, ionic liquid-based bacterial cellulose membranes, topical small interfering RNA (siRNA) delivery, and ionogels as a possible solutions for overcoming the challenges associated with the topical route. This review also takes into account the toxicological aspects and biomedical applications of ionic liquids.

Biocompatible Cationic Lipoamino Acids as Counterions for Oral Administration of API-Ionic Liquids

Purpose

The use of ionic liquids (ILs) in drug delivery has focused attention on non-toxic IL counterions. Cationic lipids can be used to form ILs with weakly acidic drugs to enhance drug loading in lipid-based formulations (LBFs). However, cationic lipids are typically toxic. Here we explore the use of lipoaminoacids (LAAs) as cationic IL counterions that degrade or digest in vivo to non-toxic components.

Methods

LAAs were synthesised via esterification of amino acids with fatty alcohols to produce potentially digestible cationic LAAs. The LAAs were employed to form ILs with tolfenamic acid (Tol) and the Tol ILs loaded into LBF and examined in vitro and in vivo.

Results

Cationic LAAs complexed with Tol to generate lipophilic Tol ILs with high drug loading in LBFs. Assessment of the LAA under simulated digestion conditions revealed that they were susceptible to enzymatic degradation under intestinal conditions, forming biocompatible FAs and amino acids. In vitro dispersion and digestion studies of Tol ILs revealed that formulations containing digestible Tol ILs were able to maintain drug dispersion and solubilisation whilst the LAA were breaking down under digesting conditions. Finally, in vivo oral bioavailability studies demonstrated that oral delivery of a LBF containing a Tol IL comprising a digestible cationic lipid counterion was able to successfully support effective oral delivery of Tol.

Conclusions

Digestible LAA cationic lipids are potential IL counterions for weakly acidic drug molecules and digest in situ to form non-toxic breakdown products.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11095-022-03305-y.

Ionic Liquids for Enhanced Drug Delivery: Recent Progress and Prevailing Challenges

Ionic liquids (ILs) are a class of nonmolecular compounds composed only of ions. Compared with traditional organic solvents, ILs have the advantages of wide chemical space, diverse and flexible structures, negligible vapor pressure, and high thermal stability, which make them widely used in many fields of modern science, such as chemical synthesis and catalytic decomposition, electrochemistry, biomass conversion, and biotransformation biotechnology. Because of their special characteristics, ILs have been favored in the pharmaceutical field recently, especially for the development of efficient drug delivery systems. So far, ILs have been successfully designed to promote the dissolution of poorly soluble drugs and the destruction of physiological barriers, such as the tight junction between the stratum corneum and the intestinal epithelium. In addition, ILs can also be combined with other drug strategies to stabilize the structure of small molecules. This Review mainly introduces the application of ILs in drug delivery, emphasizes the potential mechanism of ILs, and presents the key research directions of ILs in the future.

Applications of choline-based ionic liquids in drug delivery

Ionic liquids (ILs) usually refer to kinds of salts with melting point below 100 °C and are composed of definite anions and cations. In recent years, in addition to the field of material engineering, the applications of ILs have been extended to biomedical application. As a solubilizer, skin penetration enhancer, antibacterial agent, and macromolecular stabilizer of poorly soluble active pharmaceutical ingredients, ILs have attracted great attention in the field of pharmaceutical research. Among them, choline-based ILs are very popular in the field of drug delivery due to their biocompatibility, biodegradability, low toxicity or non-toxicity and other characteristics. This article mainly reviews the applications of choline-based ILs formed by choline and organic acid and choline-based ionic liquids-pharmaceutical active ingredients in transdermal delivery, topical delivery and oral delivery.

The Emerging Role of Ionic Liquid-Based Approaches for Enhanced Skin Permeation of Bioactive Molecules: A Snapshot of the Past Couple of Years

Topical and transdermal delivery systems are of undeniable significance and ubiquity in healthcare, to facilitate the delivery of active pharmaceutical ingredients, respectively, onto or across the skin to enter systemic circulation. From ancient ointments and potions to modern micro/nanotechnological devices, a variety of approaches has been explored over the ages to improve the skin permeation of diverse medicines and cosmetics. Amongst the latest investigational dermal permeation enhancers, ionic liquids have been gaining momentum, and recent years have been prolific in this regard. As such, this review offers an outline of current methods for enhancing percutaneous permeation, highlighting selected reports where ionic liquid-based approaches have been investigated for this purpose. Future perspectives on use of ionic liquids for topical delivery of bioactive peptides are also presented.

Oral delivery of proteins and peptides: Challenges, status quo and future perspectives

Proteins and peptides (PPs) have gradually become more attractive therapeutic molecules than small molecular drugs due to their high selectivity and efficacy, but fewer side effects. Owing to the poor stability and limited permeability through gastrointestinal (GI) tract and epithelia, the therapeutic PPs are usually administered by parenteral route. Given the big demand for oral administration in clinical use, a variety of researches focused on developing new technologies to overcome GI barriers of PPs, such as enteric coating, enzyme inhibitors, permeation enhancers, nanoparticles, as well as intestinal microdevices. Some new technologies have been developed under clinical trials and even on the market. This review summarizes the history, the physiological barriers and the overcoming approaches, current clinical and preclinical technologies, and future prospects of oral delivery of PPs.