Ionic Liquids and Deep Eutectic Solvents for Application in Pharmaceutics

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.

Active pharmaceutical ingredient-ionic liquids assisted follicular co-delivery of ferulic acid and finasteride for enhancing targeted anti-alopecia

Androgenetic alopecia (AGA) is the primary hair loss with impairing patients' quality of life. Finasteride (FIN) is an SRD5A2 inhibitor for AGA treatment, but oral FIN causes systemic adverse effects. Topical FIN delivery is anticipated to overcome this problem. Ferulic acid (FA) is a natural phenolic acid with vascular remodeling and anti-inflammatory effects. Herein, an active pharmaceutical ingredient ionic liquid (API IL) based on choline and FA (CF-IL) is for the first time constructed to load FIN for fabricating FIN CF-IL. CF-IL aims to act as carriers and cargos and enhance hair follicle (HF) co-delivery of FA and FIN for synergistic anti-alopecia. Thermal and spectroscopic analysis combined with quantum chemistry calculations and molecular dynamics confirm the formation of CF-IL. The CF-IL simultaneously increases the solubility of FA (∼648-fold) and FIN (∼686-fold), enhances the permeation and retention of FIN and FA through the follicular pathway, and promotes cellular uptake. FIN CFIL regulates the abnormal mRNA expressions in dihydrotestosterone-irritated hDPCs, and promotes hair regrowth in AGA mice in a combined manner with FIN and FA. These findings suggest that FA-based API IL is a promising approach for percutaneously co-delivering FA and FIN to HF, providing an enhanced targeting treatment for AGA.

Solubility and Solvation Properties of Pharmaceutically Active Ionic Liquid Benzocainium Ibuprofenate in Natural Deep Eutectic Solvent Menthol-Lauric Acid

Due to their appealing physiochemical properties, particularly in the pharmaceutical industry, deep eutectic solvents (DESs) and ionic liquids (ILs) are utilized in various research fields and industries. The presented research analyzes the thermodynamic properties of a deep eutectic solvent created from natural molecules, menthol and lauric acid in a 2:1 molar ratio, and an ionic liquid based on two active pharmaceutical ingredients, benzocainium ibuprofenate. Initially, the low solubility of benzocainium ibuprofenate in water was observed, and a hydrophobic natural deep eutectic mixture of menthol:lauric acid in a 2:1 ratio was prepared to improve benzocainium ibuprofenate solubility. In order to determine the solvent properties of DESs and ILs mixtures at different temperatures and their molecular interactions to enhance the solvent performance, the apparent molar volume, limiting apparent molar expansibility, and viscosity B coefficient were estimated in temperature range from 293.15 K to 313.15 K and varying concentration of benzocainium ibuprofenate.

In Vitro Antimicrobial Studies of Mesoporous Silica Nanoparticles Comprising Anionic Ciprofloxacin Ionic Liquids and Organic Salts

The combination of active pharmaceutical ingredients in the form of ionic liquids or organic salts (API-OSILs) with mesoporous silica nanoparticles (MSNs) as drug carriers can provide a useful tool in enhancing the capabilities of current antibiotics, especially against resistant strains of bacteria. In this publication, the preparation of a set of three nanomaterials based on the modification of a MSN surface with cholinium ([MSN-Chol][Cip]), 1-methylimidazolium ([MSN-1-MiM][Cip]) and 3-picolinium ([MSN-3-Pic][Cip]) ionic liquids coupled with anionic ciprofloxacin have been reported. All ionic liquids and functionalized nanomaterials were prepared through sustainable protocols, using microwave-assisted heating as an alternative to conventional methods. All materials were characterized through FTIR, solution ¹H NMR, elemental analysis, XRD and N₂ adsorption at 77 K. The prepared materials showed no in vitro cytotoxicity in fibroblasts viability assays. The minimum inhibitory concentration (MIC) for all materials was tested against Gram-negative K. pneumoniae and Gram-positive Enterococcus spp., both with resistant and sensitive strains. All sets of nanomaterials containing the anionic antibiotic outperformed free ciprofloxacin against resistant and sensitive forms of K. pneumoniae, with the prominent case of [MSN-Chol][Cip] suggesting a tenfold decrease in the MIC against sensitive strains. Against resistant K. pneumoniae, a five-fold decrease in the MIC was observed for all sets of nanomaterials compared with neutral ciprofloxacin. Against Enterococcus spp., only [MSN-1-MiM][Cip] was able to demonstrate a slight improvement over the free antibiotic.

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.

Long-ranged heterogeneous structure in aqueous solutions of the deep eutectic solvent choline and geranate at the liquid-vapor interface

The deep eutectic solvent choline and geranate (CAGE) has shown promise in many therapeutic applications. CAGE facilitates drug delivery through unique modes of action making it an exciting therapeutic option. We examine the behavior of aqueous CAGE solutions at a liquid-vapor interface. We find that the liquid-vapor interface induces large oscillations in the density, which corresponds to spontaneous segregation into regions enriched with geranate and geranic acid and other regions enriched with water and choline. These heterogeneities are observed to extend nanometers into the liquid. Additionally, we find that the geranate and geranic acid orient so that their polar carboxyl or carboxylate groups are on average pointed toward the layer containing water and choline. Finally, we report surface tension and thermal expansion coefficients for various concentrations of aqueous CAGE. We find a non-monotonic trend in the surface tension with concentration. The structural and thermodynamic properties we report provide a new perspective on CAGE behavior, which helps deduce the action of CAGE in more sophisticated systems and inspire other studies and applications of CAGE and related materials.

Structural, Thermal, and Storage Stability of Rapana Thomasiana Hemocyanin in the Presence of Cholinium-Amino Acid-Based Ionic Liquids

Novel biocompatible compounds that stabilize proteins in solution are in demand for biomedical and/or biotechnological applications. Here, we evaluated the effect of six ionic liquids, containing mono- or dicholinium [Chol]_1or2 cation and anions of charged amino acids such as lysine [Lys], arginine [Arg], aspartic acid [Asp], or glutamic acid [Glu], on the structure, thermal, and storage stability of the Rapana thomasiana hemocyanin (RtH). RtH is a protein with huge biomedicinal potential due to its therapeutic, drug carrier, and adjuvant properties. Overall, the ionic liquids (ILs) induce changes in the secondary structure of RtH. However, the structure near the Cu-active site seems unaltered and the oxygen-binding capacity of the protein is preserved. The ILs showed weak antibacterial activity when tested against three Gram-negative and three Gram-positive bacterial strains. On the contrary, [Chol][Arg] and [Chol][Lys] exhibited high anti-biofilm activity against E. coli 25213 and S. aureus 29213 strains. In addition, the two ILs were able to protect RtH from chemical and microbiological degradation. Maintained or enhanced thermal stability of RtH was observed in the presence of all ILs tested, except for RtH-[Chol]₂[Glu].

Boosting Antimicrobial Activity of Ciprofloxacin by Functionalization of Mesoporous Silica Nanoparticles

Mesoporous silica nanoparticles (MSNs) are very promising nanomaterials for treating bacterial infections when combined with pharmaceutical drugs. Herein, we report the preparation of two nanomaterials based on the immobilization of ciprofloxacin in mesoporous silica nanoparticles, either as the counter-ion of the choline derivative cation (MSN-[Ch][Cip]) or via anchoring on the surface of amino-group modified MSNs via an amide bond (MSN-Cip). Both nanomaterials were characterized by TEM, FTIR and solution ¹H NMR spectroscopies, elemental analysis, XRD and N₂ adsorption at 77 K in order to provide the desired structures. No cytotoxicity from the prepared mesoporous nanoparticles on 3T3 murine fibroblasts was observed. The antimicrobial activity of the nanomaterials was determined against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Klebsiella pneumoniae) bacteria and the results were promising against S. aureus. In the case of B. subtilis, both nanomaterials exhibited higher antimicrobial activity than the precursor [Ch][Cip], and in the case of K. pneumoniae they exhibited higher activity than neutral ciprofloxacin.

Application of Ionic Liquids for Chemical Demulsification: A Review

In recent years, ionic liquids have received increasing interests as an effective demulsifier due to their characteristics of non-flammability, thermal stability, recyclability, and low vapor pressure. In this study, emulsion formation and types, chemical demulsification system, the application of ionic liquids as a chemical demulsifier, and key factors affecting their performance were comprehensively reviewed. Future challenges and opportunities of ionic liquids application for chemical demulsification were also discussed. The review indicted that the demulsification performance was affected by the type, molecular weight, and concentration of ionic liquids. Moreover, other factors, including the salinity of aqueous phase, temperature, and oil types, could affect the demulsification process. It can be concluded that ionic liquids can be used as a suitable substitute for commercial demulsifiers, but future efforts should be required to develop non-toxic and less expensive ionic liquids with low viscosity, and the demulsification efficiency could be improved through the application of ionic liquids with other methods such as organic solvents.