A Deep Eutectic Solvent-Based Approach to Intravenous Formulation

Assessing the Toxicity of Terpene- and Amino Acid-Based Natural Deep Eutectic Solvents

Over the past decade, there has been a significant increase in the discovery of greener solvents for industrial applications. In this context, deep eutectic solvents (DESs) have emerged as promising candidates across various sectors, including biomass conversion, paper and pulp, pharmaceuticals, and textiles. A new class of DESs, known as natural deep eutectic solvents (NADESs), is derived from natural chemicals and is expected to be more environmentally friendly. However, research into the environmental impact and toxicity of NADESs is still limited. Given the broad applications of DESs and the urgent need for sustainable alternatives, studying their toxicity is crucial. In our current study, we focused on NADESs formulated from menthol, thymol, and amino acid. We assessed their toxicity on different cell lines using standard biochemical assays. Remarkably, our findings also indicate that these NADESs exhibit low toxicity in the HaCaT cell line and a mice blood sample. We also found that all of the tested NADESs have shown better antimicrobial property values compared to the individual components of NADESs, indicating the importance of NADES formulation for applications. Among the tested NADESs, menthol:thymol (1:1) showed the best antibacterial properties. These results hold significant implications for the development of NADESs in industrial applications, suggesting a path forward for the adoption of greener and safer solvents.

Intracerebral delivery of the ionic liquid form of edaravone via nose-to-brain delivery route for treating cerebral ischemia/reperfusion injury

Nose-to-brain drug delivery via intranasal administration is expected to be a promising route for efficient delivery to the central nervous system (CNS), as it allows for noninvasive and direct delivery of drugs to the CNS by avoiding the blood-brain barrier. However, the delivery efficiency of the administered drugs is still limited owing to poor mucosal epithelium permeation and mucociliary clearance. The use of ionic liquids (ILs) has garnered substantial attention in biomedical engineering for their potential to improve the physicochemical properties of active pharmaceutical ingredients and overcome biological barriers that impede drug delivery to the desired sites. We hypothesized that ILs are promising delivery platforms for achieving efficient permeation through the mucosal epithelium for nose-to-brain delivery. Herein, we newly developed IL forms of edaravone (edaravone-ILs), a clinically used cerebroprotectant, and applied them to nose-to-brain delivery to treat cerebral ischemia/reperfusion (I/R) injury. Through a series of in vitro studies, we found the biocompatible edaravone-IL which exhibits superior antioxidant activity and enhanced water solubility compared to that with native edaravone. Following intranasal administration, edaravone delivery to the brain was significantly more efficient with edaravone-IL than that with the edaravone solution. Moreover, the intranasal administration of edaravone-IL significantly ameliorated cerebral I/R injury in transient middle cerebral artery-occluded rats. These findings suggest that ILs offer a promising way for efficient intracerebral drug delivery via the nose-to-brain route and edaravone-IL could serve as a potential cerebroprotective agent for treating cerebral I/R injury.

3D printed eutectogel dissolving microneedles patch loaded with chitosan-based nanoparticles for diabetic wound management

Dissolving microneedles (DMNs) represent promising platforms for painless transdermal drug delivery and biosensing, yet integrating multifunctionality with sustainable recyclability via photo-curable additive manufacturing strategy remains challenging. Here we report a multifunctional, pioneering 3D-printed DMNs patch combining a ternary polymerizable deep eutectic solvent (PDES) system with a recyclable eutectogel backing layer. DMNs, formulated with biocompatible choline chloride, itaconic acid, and N-vinyl-2-pyrrolidone, enable rapid photopolymerization and excellent mechanical strength for effective skin penetration. Chitosan-based glucose-responsive nanoparticles incorporated into the DMNs facilitate controlled and responsive drug release, demonstrating in diabetic rats a rapid blood glucose reduction to 18.7 % of initial levels within 3 h post-administration, sustained for 4 h while minimizing hypoglycemic risk. The conductive, adhesive, and antibacterial eutectogel backing layer offers superior properties for wound dressing and wearable sensors, also serving as a real-time health monitor for human movements. In diabetic mouse models, the CHPG-TA@CUR-DMN@NPs system achieved 68.08 % wound closure by day 10, significantly accelerating healing with reduced inflammation and scarring. The backing layer is designed for easy dissolution and recycling after use, highlighting the eco-friendly and cost-effective nature of our all-in-one integrated multi-material DMNs platform.

Deep eutectic solvents in analysis, delivery and chemistry of pharmaceuticals

Deep eutectic solvents (DES) have an emerging scientific role, assisting modern pharmaceutics. They are uniquely supporting the resolution of crucial issues, such as the effective extraction and isolation of bio-actives. They act as media and catalysts for pharmaceutical drug synthesis, and as green solvents and modifiers in pharmaceutical analysis. Their role in pharmaceutical formulation and drug delivery is also up-and-coming, for instance, as alternative drug-solubilizing agents, drug stabilizers and functional additives, as therapeutic deep eutectic solvents, deep eutectic API, and monomers and reaction media for the synthesis of biomaterials for advanced drug delivery. The DES also help transforming medicinal/pharmaceutical chemistry. Although DES were described in 1918, their first pharmaceutical use is only reported in 1960. In view of their broad applicability in pharmaceutics, it may be interesting to review their history, origin, evolution, potential advantages, limitations, and specific applications as green solvents. A chronological and comparative study of the literature showed the important role of DES in green approaches for modern pharmaceuticals. The concepts, applications, and outcomes of DES in pharmaceutical analysis, formulation/drug delivery, and pharmaceutical/medicinal chemistry are presented. A comprehensive outline of the atypical applications of DES as effective green solvents in pharmaceutical bioactive extraction was assessed. Efforts to present classifications of DES explored in pharmaceuticals were also made. The present manuscript also covers computational trend, adds on commercial aspects with potential future applications of DES in pharmaceutical sciences.

Responsive deep eutectic solvents: mechanisms, applications and their role in sustainable chemistry

In an era so focused on sustainability, it is important to improve chemical processes by developing and using more environmentally friendly solvents and technologies. Deep eutectic solvents (DES) have proven to be a promising replacement for conventional solvents. In recent years, a new type of DES has emerged that responds to various stimuli. These responsive DES (RDES) may offer all the advantages of DES while allowing the recycling and reuse of solvents. As such, RDES can further contribute to a greener future. This review provides an overview of the diverse types of RDES, their switching mechanisms and their application in several fields. Lastly, it offers a critical perspective on current shortcomings and prospects.

Solubilization techniques used for poorly water-soluble drugs

About 40% of approved drugs and nearly 90% of drug candidates are poorly water-soluble drugs. Low solubility reduces the drugability. Effectively improving the solubility and bioavailability of poorly water-soluble drugs is a critical issue that needs to be urgently addressed in drug development and application. This review briefly introduces the conventional solubilization techniques such as solubilizers, hydrotropes, cosolvents, prodrugs, salt modification, micronization, cyclodextrin inclusion, solid dispersions, and details the crystallization strategies, ionic liquids, and polymer-based, lipid-based, and inorganic-based carriers in improving solubility and bioavailability. Some of the most commonly used approved carrier materials for solubilization techniques are presented. Several approved poorly water-soluble drugs using solubilization techniques are summarized. Furthermore, this review summarizes the solubilization mechanism of each solubilization technique, reviews the latest research advances and challenges, and evaluates the potential for clinical translation. This review could guide the selection of a solubilization approach, dosage form, and administration route for poorly water-soluble drugs. Moreover, we discuss several promising solubilization techniques attracting increasing attention worldwide.

A novel m-xylylene-diamine/glucose based-supramolecular eutectogels with tissue clearing for three dimensional histological imaging

Hydrogel-based tissue clearing technologies have shown significant promise for deep-tissue imaging and subcellular-level optical 3D reconstruction of whole organs. This study proposes a novel approach utilizing a deep eutectic solvent (DES) formulated with glucose and m-xylylene-diamine (MXDA) to create a highly efficient tissue-clearing hydrogel system named the passive hydrogel clearing system (PHCS). PHCS achieved efficient tissue clearing through a single-step tissue gelation process. The resulting hydrogel-tissue complex exhibited thermoreversible properties, transitioning into a sol state upon heating and vice versa upon cooling. Notably, PHCS enabled media embedding, facilitating immunofluorescence histopathology. Additionally, the system demonstrated compatibility with various fluorescent probes, particularly lipophilic dyes. Our study successfully employed PHCS for the reconstruction of vascular structures within the intestine, enabling the generation of a 3D pathology model. These findings suggest that PHCS is a promising novel method for fabricating hydrogels for tissue clearing and holds great potential for application as a mounting medium for morphological imaging.

Deep Eutectic Solvents Enhancing Drug Solubility and Its Delivery

Deep eutectic solvents (DES) are environmentally friendly solvents with the potential to dissolve bioactive compounds without affecting their characteristics. DES has special qualities that can be customized to meet the unique characteristics of a biomolecule/active pharmaceutical ingredient (API) in accordance with various therapeutic needs, providing a reliable approach in opening the door for the creation of cutting-edge drug formulations by resolving solubility issues in pharmaceutics. This study outlines newly developing approaches to solve the problem of inefficient API extraction due to poor solubility. These emerging strategies also have the capacity to alter the chemical and physical stability of API, which triggers drug's shelf life and their possible health benefits. It is anticipated that the highlighted methods and processes will be developed to capitalize on the DES potential to improve drug solubility and delivery in the pharmaceutical sector.

Pharmaceutical applications of therapeutic deep eutectic systems (THEDES) in maximising drug delivery

The issue of poor solubility of active pharmaceutical ingredients (APIs) has been a salient area of investigation and novel drug delivery systems are being developed to improve the solubility of drugs, enhance their permeability and thereby their efficacy. Several techniques for solubilization enhancement of poorly soluble drugs are often employed at various stages of pharmaceutical drug product development. One such delivery system is the therapeutic deep eutectic system (THEDES), which showed great potential in the enhancement of solubility and permeability of drugs and ultimately augmenting their bioavailability. THEDES are made by mixing drugs with deep eutectic solvents (DESs) in a definite molar ratio by the hit and trial method. The DESs are a new class of green solvents which are non-toxic, cheap, easy to prepare, biodegradable and have multiple applications in the pharmaceutical industry. The terminologies such as ionic liquids (ILs), DES, THEDES, and therapeutic liquid eutectic systems (THELES) have been very much in use recently, and it is important to highlight the pharmaceutical applications of these unexplored reservoirs in drug solubilization enhancement, drug delivery routes, and in the management of various diseases. This review is aimed at discussing the components, formulation strategies, and routes of administration of THEDES that are used in developing the formulation. Also, the major pharmaceutical applications of THEDES in the treatment of various metabolic and non-metabolic diseases are reviewed.

A green method to extract rutin from Sophora japonica L

Sophora japonica L. contains high levels of rutin, which has great potential for use in pharmaceutical products for the treatment of diseases related to the cardiovascular and circulatory systems. We proposed a method of extracting rutin from S. japonica by using a green solvent.•Green deep eutectic solvents (DESs) of choline chloride and ethylene glycol (ChCl-Eth) showed the highest extraction efficiency of rutin from S. japonica.•Under optimal conditions, the extraction yield of ChCl-Eth was 1.34 times higher than that of methanol as solvent.•Rutin was recovered from the DES extracts using water as the antisolvent with a high recovery yield, and the DESs of ChCl-Eth could be productively recovered and reused at least 3 times.

Development of Edaravone Ionic Liquids and Their Application for the Treatment of Cerebral Ischemia/Reperfusion Injury

Preparation of the ionic liquid (IL) form of active pharmaceutical ingredients (APIs), termed API-IL, has attracted attention because it can improve upon certain disadvantages of APIs, such as poor water solubility and low stability. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) is a clinically approved cerebroprotective agent against ischemic stroke and amyotrophic lateral sclerosis, while new formulations that enable improvement of its physicochemical properties and biodistribution are desired. Herein, we report a newly developed API-IL of edaravone (edaravone-IL), in which edaravone is used as an anionic molecule. We investigated the physicochemical properties of edaravone-IL and its therapeutic effect against cerebral ischemia/reperfusion (I/R) injury, a secondary injury after an ischemic stroke. Among the cationic molecules used for edaravone-IL preparation, the IL prepared with tetrabutylphosphonium cation existed as a liquid at room temperature, and significantly increased the water solubility of edaravone without decreasing its antioxidative activity. Importantly, edaravone-IL formed negatively charged nanoparticles upon suspension in water. Intravenous administration of edaravone-IL showed significantly higher blood circulation time and lower distribution in the kidney compared with edaravone solution. Moreover, edaravone-IL significantly suppressed brain cell damage and motor functional deficits in model rats of cerebral I/R injury and showed comparable cerebroprotective effect to edaravone. Taken together, these results suggest that edaravone-IL could be a new form of edaravone with superior physicochemical properties and could be useful for the treatment of cerebral I/R injury.

Application of deep eutectic solvents in protein extraction and purification

Deep eutectic solvents (DESs) are a mixture of hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) molecules that can consist, respectively, of natural plant metabolites such as sugars, carboxylic acids, amino acids, and ionic molecules, which are for the vast majority ammonium salts. Media such as DESs are modular tools of sustainability that can be pointed toward the extraction of bioactive molecules due to their excellent physicochemical properties, their relatively low price, and accessibility. The present review focuses on the application of DESs for protein extraction and purification. The in-depth effects and principles that apply to DES-mediated extraction using various renewable biomasses will be discussed as well. One of the most important observations being made is that DESs have a clear ability to maintain the biological and/or functional activity of the extracted proteins, as well as increase their stability compared to traditional solvents. They demonstrate true potential for a reproducible but more importantly, scalable protein extraction and purification compared to traditional methods while enabling waste valorization in some particular cases.

Deep Eutectic Solvents: Are They Safe?

Deep eutectic solvents (DESs) are a relatively new type of solvent that have attracted the attention of the scientific community due to their environmentally friendly properties and their versatility in many applications. Many possible DESs have been described and, thus, it is not easy to unequivocally characterize and generalize their properties. This is especially important in the case of the (eco)toxicity information that can be found for these mixtures. In this review, we collect data on the human and environmental toxicity of DESs, with the aim of gathering and exploring the behavioral patterns of DESs. The toxicity data found were analyzed attending to different factors: hydrogen bond donors or acceptors that form part of the eutectic mixture, pH, and the presence of organic acids in the DES molar ratio of the components, or interactions with natural compounds. In the case of ecotoxicity, results generally depend on the biomodel studied, along with other factors that have been also revised. Finally, we also carried out a revision of the biodegradation of DESs.