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

Prostate tissue ablation and drug delivery by an image-guided injectable ionic liquid in ex vivo and in vivo models

Benign prostatic hyperplasia and prostate cancer are often associated with lower urinary tract symptoms, which can severely affect patient quality of life. To address this challenge, we developed and optimized an injectable compound, prostate ablation and drug delivery agent (PADA), for percutaneous prostate tissue ablation and concurrently delivered therapeutic agents. PADA is an ionic liquid composed of choline and geranic acid mixed with anticancer therapeutics and a contrast agent. The PADA formulation was optimized for mechanical properties compatible with hand injection, diffusion capability, cytotoxicity against prostate cells, and visibility of an x-ray contrast agent. PADA also exhibited antibacterial properties against highly resistant clinically isolated bacteria in vitro. Ultrasound-guided injection, dispersion of PADA in the tissue, and tissue ablation were tested ex vivo in healthy porcine, canine, and human prostates and in freshly resected human tumors. In vivo testing was conducted in a murine subcutaneous tumor model and in the canine prostate. In all models, PADA decreased the number of viable cells in the region of dispersion and supported the delivery of nivolumab throughout a portion of the tissue. In canine survival experiments, there were no adverse events and no impact on urination. The injection approach was easy to perform under ultrasound guidance and produced a localized effect with a favorable safety profile. These findings suggest that PADA is a promising therapeutic prostate ablation strategy to treat lower urinary tract symptoms.

A bio-ionic liquid based self-healable and adhesive ionic hydrogel for the on-demand transdermal delivery of a chemotherapeutic drug

The non-invasive nature and potential for sustained release make transdermal drug administration an appealing treatment option for cancer therapy. However, the strong barrier of the stratum corneum (SC) poses a challenge for the penetration of hydrophilic chemotherapy drugs such as 5-fluorouracil (5-FU). Due to its biocompatibility and capacity to increase drug solubility and permeability, especially when paired with chemical enhancers, such as oleic acid (OA), which is used in this work, choline glycinate ([Cho][Gly]) has emerged as a potential substance for transdermal drug delivery. In this work, we examined the possibility of transdermal delivery of 5-FU for the treatment of breast cancer using an ionic hydrogel formulation consisting of [Cho][Gly] with OA. Small angle neutron scattering, rheological analysis, field emission scanning electron microscopy, and dynamic light scattering analysis were used to characterize the ionic hydrogel. The non-covalent interactions present between [Cho][Gly] and OA were investigated by computational simulations and FTIR spectroscopy methods. When subjected to in vitro drug permeation using goat skin in a Franz diffusion cell, the hydrogel demonstrated sustained release of 5-FU and effective permeability in the order: [Cho][Gly]-OA gel > [Cho][Gly] > PBS (control). The hydrogel also demonstrated 92% cell viability after 48 hours for the human keratinocyte cell line (HaCaT cells) as well as the normal human cell line L-132. The breast cancer cell line MCF-7 and the cervical cancer cell line HeLa were used to study in vitro cytotoxicity that was considerably affected by the 5-FU-loaded hydrogel. These results indicate the potential of the hydrogel as a transdermal drug delivery vehicle for the treatment of breast cancer.

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.

Catheter-Directed Ionic Liquid Embolic Agent for Rapid Portal Vein Embolization, Segmentectomy, and Bile Duct Ablation

Embolic materials currently in use for portal vein embolization (PVE) do not treat the tumor, which poses a risk for tumor progression during the interval between PVE and surgical resection. Here, is developed an ionic-liquid-based embolic material (LEAD) for portal vein embolization, liver ablation, and drug delivery. LEAD is optimized and characterized for diffusivity, X-ray visibility, and cytotoxicity. In the porcine renal embolization model, LEAD delivered from the main renal artery reached vasculature down to 10 microns with uniform tissue ablation and delivery of small and large therapeutics. In non-survival and survival porcine experiments, successful PVE is achieved in minutes, leading to the expected chemical segmentectomy, and delivery of a large protein drug (i.e., Nivolumab) with LEAD. In cholangiocarcinoma mouse tumor models and in ex vivo human tumors, LEAD consistently achieved an effective ablation and wide drug distribution. Furthermore, various strains of drug-resistant patient-derived bacteria showed significant susceptibility to LEAD, suggesting that LEAD may also prevent infectious complications resulting from tissue ablation. With its capabilities to embolize, ablate, and deliver therapeutics, ease of use, and a high safety profile demonstrated in animal studies, LEAD offers a potential alternative to tumor ablation with or without PVE for FLR growth.

Facile Separation of Acetic Acid from 1-Ethyl-3-methylimidazolium Acetate Ionic Liquid with the Aid of a Protic Solvent

1-Ethyl-3-methylimidazolium acetate (EmimAc), an excellent solvent for cellulosic biomass, is expected to be utilized in chemical conversion, such as in biomass acetylation with acetic anhydride. The corresponding carboxylic acid, acetic acid (AcH), is quantitatively generated as a byproduct and should be separated from EmimAc for recycling. However, the strong interaction between EmimAc and AcH makes their separation difficult under moderate conditions. This study examined the efficacy of protic solvents in distillation and extraction to weaken this interaction through solvation or hydrogen-bonding interactions. The separation efficiency of AcH from EmimAc via distillation increased as the boiling point of the protic solvent increased. Water addition was more effective than the addition of alcohols with boiling points similar to those of water such as 1-propanol and 2-butanol. Furthermore, the favorable effect of water addition on the extraction of AcH was confirmed using common organic solvents, such as diisopropyl ether, diethyl ether, and ethyl acetate. The partition coefficient (α) of AcH between the aqueous and organic phases increased with an increasing dielectric constant of the organic solvent, whereas the α value of EmimAc decreased. Repeated treatments in both distillation and extraction facilitated the complete separation of AcH from EmimAc.

Ionic liquids and deep eutectic solvents for the stabilization of biopharmaceuticals: A review

Biopharmaceuticals have allowed the control of previously untreatable diseases. However, their low solubility and stability still hinder their application, transport, and storage. Hence, researchers have applied different compounds to preserve and enhance the delivery of biopharmaceuticals, such as ionic liquids (ILs) and deep eutectic solvents (DESs). Although the biopharmaceutical industry can employ various substances for enhancing formulations, their effect will change depending on the properties of the target biomolecule and environmental conditions. Hence, this review organized the current state-of-the-art on the application of ILs and DESs to stabilize biopharmaceuticals, considering the properties of the biomolecules, ILs, and DESs classes, concentration range, types of stability, and effect. We also provided a critical discussion regarding the potential utilization of ILs and DESs in pharmaceutical formulations, considering the restrictions in this field, as well as the advantages and drawbacks of these substances for medical applications. Overall, the most applied IL and DES classes for stabilizing biopharmaceuticals were cholinium-, imidazolium-, and ammonium-based, with cholinium ILs also employed to improve their delivery. Interestingly, dilute and concentrated ILs and DESs solutions presented similar results regarding the stabilization of biopharmaceuticals. With additional investigation, ILs and DESs have the potential to overcome current challenges in biopharmaceutical formulation.

Ligand-Independent Activation of Aryl Hydrocarbon Receptor and Attenuation of Glutamine Levels by Natural Deep Eutectic Solvent

Natural deep eutectic solvents (NADESs) are emerging sustainable alternatives to conventional organic solvents. Beyond their role as laboratory solvents, NADESs are increasingly explored in drug delivery and as therapeutics. Their increasing applications notwithstanding, our understanding of how they interact with biomolecules at multiple levels - metabolome, proteome, and transcriptome - within human cell remain poor. Here, we deploy integrated metabolomics, proteomics, and transcriptomics to probe how NADESs perturb the molecular landscape of human cells. In a human cell line model, we found that an archetypal NADES derived from choline and geranic acid (CAGE) significantly altered the metabolome, proteome, and transcriptome. CAGE upregulated indole-3-lactic acid and 4-hydroxyphenyllactic acid levels, resulting in ligand-independent activation of aryl hydrocarbon receptor to signal the transcription of genes with implications for inflammation, immunomodulation, cell development, and chemical detoxification. Further, treating the cell line with CAGE downregulated glutamine biosynthesis, a nutrient rapidly proliferating cancer cells require. CAGE's ability to attenuate glutamine levels is potentially relevant for cancer treatment. These findings suggest that NADESs, even when derived from natural components like choline, can indirectly modulate cell biology at multiple levels, expanding their applications beyond chemistry to biomedicine and biotechnology.

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.

Deep Eutectic Solvents: An Eco-friendly Design for Drug Engineering

In the spirit of circular economy and sustainable chemistry, the use of environmentally friendly chemical products in pharmacy has become a hot topic. In recent years, organic solvents have been the subject of a great range of restriction policies due to their harmful effects on the environment and toxicity to human health. In parallel, deep eutectic solvents (DESs) have emerged as suitable greener solvents with beneficial environmental impacts and a rich palette of physicochemical advantages related to their low cost and biocompatibility. Additionally, DESs can enable remarkable solubilizing effect for several active pharmaceutical ingredients (APIs), thus forming therapeutic DESs (TheDESs). In this work, special attention is paid to DESs, presenting a precise definition, classification, methods of preparation, and characterization. A description of natural DESs (NaDESs), i. e., eutectic solvents present in natural sources, is also reported. Moreover, the present review article is the first one to detail the different approaches for judiciously selecting the constituents of DESs in order to minimize the number of experiments. The role of DESs in the biomedical and pharmaceutical sectors and their impact on the development of successful therapies are also discussed.

The Formulation and Evaluation of Deep Eutectic Vehicles for the Topical Delivery of Azelaic Acid for Acne Treatment

The current work was aimed at the development of a topical drug delivery system for azelaic acid (AzA) for acne treatment. The systems tested for this purpose were deep eutectic systems (DESs) prepared from choline chloride (CC), malonic acid (MA), and PEG 400. Three CC to MA and eight different MA: CC: PEG400 ratios were tested. The physical appearance of the tested formulations ranged from solid and liquid to semisolid. Only those that showed liquid formulations of suitable viscosity were considered for further investigations. A eutectic mixture made from MA: CC: PEG400 1:1:6 (MCP 116) showed the best characteristics in terms of viscosity, contact angle, spreadability, partition coefficient, and in vitro diffusion. Moreover, the MCP116 showed close rheological properties to the commercially available market lead acne treatment product (Skinorin®). In addition, the formula showed synergistic antibacterial activity between the MA moiety of the DES and the AzA. In vitro diffusion studies using polyamide membranes demonstrated superior diffusion of MCP116 over the pure drug and the commercial product. No signs of skin irritation and edema were observed when MCP116 was applied to rabbit skin. Additionally, the MCP116 was found to be, physically and chemically, highly stable at 4, 25, and 40 °C for a one-month stability study.

Deep Eutectic Liquids as a Topical Vehicle for Tadalafil: Characterisation and Potential Wound Healing and Antimicrobial Activity

Deep eutectic solvents (DESs) and ionic liquids (ILs) offer novel opportunities for several pharmaceutical applications. Their tunable properties offer control over their design and applications. Choline chloride (CC)-based DESs (referred to as Type III eutectics) offer superior advantages for various pharmaceutical and therapeutic applications. Here, CC-based DESs of tadalafil (TDF), a selective phosphodiesterase type 5 (PDE-5) enzyme inhibitor, were designed for implementation in wound healing. The adopted approach provides formulations for the topical application of TDF, hence avoiding systemic exposure. To this end, the DESs were chosen based on their suitability for topical application. Then, DES formulations of TDF were prepared, yielding a tremendous increase in the equilibrium solubility of TDF. Lidocaine (LDC) was included in the formulation with TDF to provide a local anaesthetic effect, forming F01. The addition of propylene glycol (PG) to the formulation was attempted to reduce the viscosity, forming F02. The formulations were fully characterised using NMR, FTIR and DCS techniques. According to the obtained characterisation results, the drugs were soluble in the DES with no detectable degradation. Our results demonstrated the utility of F01 in wound healing in vivo using cut wound and burn wound models. Significant retraction of the cut wound area was observed within three weeks of the application of F01 when compared with DES. Furthermore, the utilisation of F01 resulted in less scarring of the burn wounds than any other group including the positive control, thus rendering it a candidate formula for burn dressing formulations. We demonstrated that the slower healing process associated with F01 resulted in less scarring potential. Lastly, the antimicrobial activity of the DES formulations was demonstrated against a panel of fungi and bacterial strains, thus providing a unique wound healing process via simultaneous prevention of wound infection. In conclusion, this work presents the design and application of a topical vehicle for TDF with novel biomedical applications.