pH-Responsive Nanostructures Based on Surface Active Fatty Acid-Protic Ionic Liquids for Imiquimod Delivery in Skin Cancer Topical Therapy

Enhanced Drug Skin Permeation by Azone-Mimicking Ionic Liquids: Effects of Fatty Acids Forming Ionic Liquids

Background/Objectives: Laurocapram (Azone) attracted attention 40 years ago as a compound with the highest skin-penetration-enhancing effect at that time; however, its development was shelved due to strong skin irritation. We had already prepared and tested an ante-enhancer (IL-Azone), an ionic liquid (IL) with a similar structure to Azone, consisting of ε-caprolactam and myristic acid, as an enhancer candidate that maintains the high skin-penetration-enhancing effect of Azone with low skin irritation. In the present study, fatty acids with different carbon numbers (caprylic acid: C8, capric acid: C10, lauric acid: C12, myristic acid: C14, and oleic acid: C18:1) were selected and used with ε-caprolactam to prepare various IL-Azones in the search for a more effective IL-Azone. Methods: Excised porcine skin was pretreated with each IL-Azone to assess the in vitro skin permeability of antipyrine (ANP) as a model penetrant. In addition, 1,3-butanediol was selected for the skin permeation test to confirm whether the effect of IL-Azone was due to fatty acids and if this effect differed depending on the concentration of IL-Azone applied. Results: The results obtained showed that C12 IL-Azone exerted the highest skin-penetration-enhancing effect, which was higher than Azone. On the other hand, many of the IL-Azones tested had a lower skin-penetration-enhancing effect. Conclusions: These results suggest the potential of C12 IL-Azone as a strong and useful penetration enhancer.

Programmable Release of Chemotherapeutics from Ferrocene-Based Injectable Hydrogels Slows Melanoma Growth

Hydrogel-based injectable drug delivery systems provide temporally and spatially controlled drug release with reduced adverse effects on healthy tissues. Therefore, they represent a promising therapeutic option for unresectable solid tumor entities. In this study, a peptide-starPEG/hyaluronic acid-based physical hydrogel is modified with ferrocene to provide a programmable drug release orchestrated by matrix-drug interaction and local reactive oxygen species (ROS). The injectable ROS-responsive hydrogel (hiROSponse) exhibits adequate biocompatibility and biodegradability, which are important for clinical applications. HiROSponse is loaded with the two cytostatic drugs (hiROSponsedox/ptx) doxorubicin (dox) and paclitaxel (ptx). Dox is a hydrophilic compound and its release is mainly controlled by Fickian diffusion, while the hydrophobic interactions between ptx and ferrocene can control its release and thus be regulated by the oxidation of ferrocene to the more hydrophilic state of ferrocenium. In a syngeneic malignant melanoma-bearing mouse model, hiROSponsedox/ptx slows tumor growth without causing adverse side effects and doubles the relative survival probability. Programmable release is further demonstrated in a tumor model with a low physiological ROS level, where dox release, low dose local irradiation, and the resulting ROS-triggered ptx release lead to tumor growth inhibition and increased survival.

Ionic Liquids in Pharmaceutical and Biomedical Applications: A Review

The unique properties of ionic liquids (ILs), such as structural tunability, good solubility, chemical/thermal stability, favorable biocompatibility, and simplicity of preparation, have led to a wide range of applications in the pharmaceutical and biomedical fields. ILs can not only speed up the chemical reaction process, improve the yield, and reduce environmental pollution but also improve many problems in the field of medicine, such as the poor drug solubility, product crystal instability, poor biological activity, and low drug delivery efficiency. This paper presents a systematic and concise analysis of the recent advancements and further applications of ILs in the pharmaceutical field from the aspects of drug synthesis, drug analysis, drug solubilization, and drug crystal engineering. Additionally, it explores the biomedical field, covering aspects such as drug carriers, stabilization of proteins, antimicrobials, and bioactive ionic liquids.

Microneedle-Assisted Transfersomes as a Transdermal Delivery System for Aspirin

Transdermal drug delivery systems offer several advantages over conventional oral or hypodermic administration due to the avoidance of first-pass drug metabolism and gastrointestinal degradation as well as patients' convenience due to a minimally invasive and painless approach. A novel transdermal drug delivery system, comprising a combination of transfersomes with either solid silicon or solid polycarbonate microneedles has been developed for the transdermal delivery of aspirin. Aspirin was encapsulated inside transfersomes using a "thin-film hydration sonication" technique, yielding an encapsulation efficiency of approximately 67.5%. The fabricated transfersomes have been optimised and fully characterised in terms of average size distribution and uniformity, surface charge and stability (shelf-life). Transdermal delivery, enhanced by microneedle penetration, allows the superior permeation of transfersomes into perforated porcine skin and has been extensively characterised using optical coherence tomography (OCT) and transmission electron microscopy (TEM). In vitro permeation studies revealed that transfersomes enhanced the permeability of aspirin by more than four times in comparison to the delivery of unencapsulated "free" aspirin. The microneedle-assisted delivery of transfersomes encapsulating aspirin yielded 13-fold and 10-fold increases in permeation using silicon and polycarbonate microneedles, respectively, in comparison with delivery using only transfersomes. The cytotoxicity of different dose regimens of transfersomes encapsulating aspirin showed that encapsulated aspirin became cytotoxic at concentrations of ≥100 μg/mL. The results presented demonstrate that the transfersomes could resolve the solubility issues of low-water-soluble drugs and enable their slow and controlled release. Microneedles enhance the delivery of transfersomes into deeper skin layers, providing a very effective system for the systemic delivery of drugs. This combined drug delivery system can potentially be utilised for numerous drug treatments.

Cation-stimulated drug delivery via lipid assembly comprising macrocyclized disaccharides - A DFT study

In the attempt to create a delivery system for an alkali-cation stimulated drug release, a computational study was conducted, aiming for the evaluation of synthetic access towards glycolipid crown ethers analogs and their potential for coordination-induced changes of packing constraints for molecular assemblies. The results disfavor amide-linkages for the creation of macrocycles around the inter-glycosidic bond of a disaccharide. Conformational changes upon cation coordination of the macrocycle decrease the intersection area for easily accessible macrocycles based on lactose. This leads to shrinking intersection areas upon alkali complexation. Maltose-based analogs, on the other hand, exhibited the targeted increase of the glycolipid intersection area and, hence, may be considered as a promising resource.

Nanotechnology-based ocular drug delivery systems: recent advances and future prospects

Ocular drug delivery has constantly challenged ophthalmologists and drug delivery scientists due to various anatomical and physiological barriers. Static and dynamic ocular barriers prevent the entry of exogenous substances and impede therapeutic agents' active absorption. This review elaborates on the anatomy of the eye and the associated constraints. Followed by an illustration of some common ocular diseases, including glaucoma and their current clinical therapies, emphasizing the significance of drug therapy in treating ocular diseases. Subsequently, advances in ocular drug delivery modalities, especially nanotechnology-based ocular drug delivery systems, are recommended, and some typical research is highlighted. Based on the related research, systematic and comprehensive characterizations of the nanocarriers are summarized, hoping to assist with future research. Besides, we summarize the nanotechnology-based ophthalmic drugs currently on the market or still in clinical trials and the recent patents of nanocarriers. Finally, inspired by current trends and therapeutic concepts, we provide an insight into the challenges faced by novel ocular drug delivery systems and further put forward directions for future research. We hope this review can provide inspiration and motivation for better design and development of novel ophthalmic formulations.

An Imidazolium-Based Ionic Liquid as a Model to Study Plasticization Effects on Cationic Polymethacrylate Films

Ionic liquids (ILs) have been touted as effective and environmentally friendly agents, which has driven their application in the biomedical field. The study compares the effectiveness of an IL agent, 1-hexyl-3-methyl imidazolium chloride ([HMIM]Cl), to current industry standards for plasticizing a methacrylate polymer. Industrial standards glycerol, dioctyl phthalate (DOP) and the combination of [HMIM]Cl with a standard plasticizer was also evaluated. Plasticized samples were evaluated for stress-strain, long-term degradation, thermophysical characterizations, and molecular vibrational changes within the structure, and molecular mechanics simulations were performed. Physico-mechanical studies showed that [HMIM]Cl was a comparatively good plasticizer than current standards reaching effectiveness at 20-30% w/w, whereas plasticizing of standards such as glycerol was still inferior to [HMIM]Cl even at concentrations up to 50% w/w. Degradation studies show HMIM-polymer combinations remained plasticized for longer than other test samples, >14 days, compared to glycerol <5 days, while remaining more pliable. The combination of [HMIM]Cl-DOP was effective at concentrations >30% w/w, demonstrating remarkable plasticizing capability and long-term stability. ILs used as singular agents or in tandem with other standards provided equivalent or better plasticizing activity than the comparative free standards.

pH and its applications in targeted drug delivery

Physiologic pH is vital for the normal functioning of tissues and varies in different parts of the body. The varying pH of the body has been exploited to design pH-sensitive smart oral, transdermal and vaginal drug delivery systems (DDS). The DDS demonstrated promising results in hard-to-treat diseases such as cancer and Helicobacter pylori infection. In some cases, a change in pH of tissues or body fluids has also been employed as a useful diagnostic biomarker. This paper aims to comprehensively review the development and applications of pH-sensitive DDS as well as recent advances in the field.

In vitro anti-melanoma activity of imiquimod in ultradeformable nanovesicles

BACKGROUND

The wide spectrum of antitumoral mechanisms of imiquimod (IMQ), made it a good candidate for topical therapy of melanoma. However, physicochemical properties make IMQ formulation a difficult task. Solubility and skin penetration of IMQ are increased when loaded into ultradeformable nanovesicles.

OBJECTIVE

Survey the in vitro anti-melanoma activity of IMQ loaded into two types of ultradeformable nanovesicles: archaeosomes (UDA-IMQ) (containing sn-2,3 ether-linked phytanyl saturated archaeolipids extracted from Halorubrum tebenquichense) and liposomes lacking archaeolipids (UDL-IMQ).

METHODS

We prepared and structurally characterized UDA-IMQ and UDL-IMQ. Cytotoxicity was determined on human melanoma cells (SK-Mel-28) and keratinocytes (HaCaT cells) by MTT assay and LDH release. The cellular uptake was determined by flow cytometry. Apoptosis/necrosis induction was determined by fluorescence microscopy after double staining with YO-PRO-1® and propidium iodide.

RESULTS

Neither IMQ nor IMQ-nanovesicles reduced the viability of HaCaT cells; but UDL-IMQ (371 nm, -24 mV ζ potential, 31 µg IMQ/mg lipids) and UDA-IMQ (216 nm, -32 mV ζ potential, 61 µg IMQ/mg lipids) showed time and concentration-dependent cytotoxicity on SK-Mel-28 that resulted between 4 and 33 folds higher than free IMQ, respectively. While both UDA-IMQ and UDL-IMQ retained 60% of IMQ against dilution, UDA-IMQ uptaken by SK-Mel-28 cells was nine-fold higher than UDL-IMQ. UDL-IMQ induced early apoptosis, but UDA-IMQ induced both apoptosis and necrosis on SK-Mel-28 cells.

CONCLUSIONS

UDA-IMQ was innocuous to keratinocytes but was highly uptaken and induced apoptosis and necrosis on melanoma cells, being a candidate for future investigations as adjuvant topical anti-melanoma therapy.

The Fabrication of Docetaxel-Containing Emulsion for Drug Release Kinetics and Lipid Peroxidation

Docetaxel (DTX)-based formulation development is still confronted with significant challenges, due to its refractory solubility and side effects on normal tissues. Inspired by the application of the transdermal drug delivery model to topical treatment, we developed a biocompatible and slow-release DTX-containing emulsion via self-assembly prepared by a high-speed electric stirring method and optimized the formulation. The results of accelerated the emulsion stability experiment showed that the emulsion prepared at 10,000 rpm/min had a stability of 89.15 ± 2.05%. The ADME, skin irritation, skin toxicity and molecular interaction between DTX and excipients were predicted via Discovery Studio 2016 software. In addition, DTX addition in oil or water phases of the emulsion showed different release rates in vitro and ex vivo. The DTX release ex vivo of the DTX/O-containing emulsion and the DTX/W-containing emulsion were 45.07 ± 5.41% and 96.48 ± 4.54%, respectively. In vitro antioxidant assays and anti-lipid peroxidation models revealed the antioxidant potential of DTX. However, DTX-containing emulsions could maintain and even enhance the antioxidant effect, both scavenging free radicals in vitro and inhibiting the process of lipid peroxidation.

Cyclosporine-loaded micelles for ocular delivery: Investigating the penetration mechanisms

Cyclosporine is an immunomodulatory drug commonly used for the treatment of mild-to-severe dry eye syndrome as well as intermediate and posterior segment diseases as uveitis. The ocular administration is however hampered by its relatively high molecular weight and poor permeability across biological barriers. The aim of this work was to identify a micellar formulation with the ability to solubilize a considerable amount of cyclosporine and promote its transport across ocular barriers. Non-ionic amphiphilic polymers used for micelles preparation were tocopherol polyethylene glycol 1000 succinate (TPGS) and Solutol® HS15. Furthermore, the addition of alpha-linolenic acid was assessed. A second aim was to evaluate micelles fate in the ocular tissues (cornea and sclera) to shed light on penetration mechanisms. This was possible by extracting and quantifying both drug and polymer in the tissues, by studying TPGS hydrolysis in a bio-relevant environment and by following micelles penetration with two-photon microscopy. Furthermore, TPGS role as permeation enhancer on the cornea, with possible irreversible modifications of tissue permeability, was analyzed. Results showed that TPGS micelles (approx. 13 nm in size), loaded with 5 mg/ml of cyclosporine, promoted drug retention in both the cornea and the sclera. Data demonstrated that micelles behavior strictly depends on the tissue: micelles disruption occurs in contact with the cornea, while intact micelles diffuse in the interfibrillar pores of the sclera and form a reservoir that can sustain over time drug delivery to the deeper tissues. Finally, cornea quickly restore the barrier properties after TPGS removal from the tissue, demonstrating its potential good tolerability for ocular application.

Recent Developments in Ionic Liquid-Assisted Topical and Transdermal Drug Delivery

Ionic liquids (ILs) have attracted growing interest as designer solvents/materials for exploring unrealized functions in many areas of research including drug formulations and delivery owing to their inherent tunable physicochemical and biological properties. The use of ILs in the pharmaceutical industry can address challenges related to the use of conventional organic solvent-based chemical permeation enhancers. Their tunability in forming ion pairs with a diverse range of ions enables the task-specific optimization of ILs at the molecular level. In particular, ILs comprising second- and third-generation cations and anions have been extensively used to design biocompatible drug delivery systems to address the challenges related to conventional topical and transdermal drug delivery, including limited permeability, high cytotoxicity, and skin irritation. This review highlights the progress in IL-related research with particular emphasis on the very recent conceptual developments in transdermal drug delivery. Technological advancement and approaches for the formation of IL-based topical and transdermal delivery systems, as well as their promising application in drug delivery, are also discussed.

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.

Enhanced In Vitro Antiviral Activity of Hydroxychloroquine Ionic Liquids against SARS-CoV-2

The development of effective antiviral drugs against SARS-CoV-2 is urgently needed and a global health priority. In light of the initial data regarding the repurposing of hydroxychloroquine (HCQ) to tackle this coronavirus, herein we present a quantitative synthesis and spectroscopic and thermal characterization of seven HCQ room temperature ionic liquids (HCQ-ILs) obtained by direct protonation of the base with two equivalents of organic sulfonic, sulfuric and carboxylic acids of different polarities. Two non-toxic and hydrophilic HCQ-ILs, in particular, [HCQH2][C1SO3]2 and [HCQH2][GlcCOO]2, decreased the virus-induced cytopathic effect by two-fold in comparison with the original drug, [HCQH2][SO4]. Despite there being no significant differences in viral RNA production between the three compounds, progeny virus production was significantly affected (p < 0.05) by [HCQH2][GlcCOO]2. Overall, the data suggest that the in vitro antiviral activities of the HCQ-ILs are most likely the result of specific intra- and intermolecular interactions and not so much related with their hydrophilic or lipophilic character. This work paves the way for the development of future novel ionic formulations of hydroxychloroquine with enhanced physicochemical properties.

TransfersomILs: From Ionic Liquids to a New Class of Nanovesicular Systems

Ionic liquids (ILs) have increasingly been studied as key materials to upgrade the performance of many pharmaceutical formulations. In controlled delivery systems, ILs have improved multiple physicochemical properties, showing the relevance of continuing to study their incorporation into these formulations. Transfersomes are biocompatible nanovesicular systems, quite useful in controlled delivery. They have promising characteristics, such as elasticity and deformability, making them suitable for cutaneous delivery. Nonetheless, their overall properties and performance may still be improved. Herein, new TransfersomILs systems to load rutin were developed and the physicochemical properties of the formulations were assessed. These systems were prepared based on an optimized formulation obtained from a Box-Behnken factorial design (BBD). The impact of imidazole-based ILs, cholinium-based ILs, and their combinations on the cell viability of HaCaT cells and on the solubility of rutin was initially assessed. The newly developed TransfersomILs containing rutin presented a smaller size and, in general, a higher association efficiency, loading capacity, and total amount of drug release compared to the formulation without IL. The ILs also promoted the colloidal stability of the vesicles, upgrading storage stability. Thus, ILs were a bridge to develop new TransfersomILs systems with an overall improved performance.

Improvement of Imiquimod Solubilization and Skin Retention via TPGS Micelles: Exploiting the Co-Solubilizing Effect of Oleic Acid

Imiquimod (IMQ) is an immunostimulant drug approved for the topical treatment of actinic keratosis, external genital-perianal warts as well as superficial basal cell carcinoma that is used off-label for the treatment of different forms of skin cancers, including some malignant melanocytic proliferations such as lentigo maligna, atypical nevi and other in situ melanoma-related diseases. Imiquimod skin delivery has proven to be a real challenge due to its very low water-solubility and reduced skin penetration capacity. The aim of the work was to improve the drug solubility and skin retention using micelles of d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), a water-soluble derivative of vitamin E, co-encapsulating various lipophilic compounds with the potential ability to improve imiquimod affinity for the micellar core, and thus its loading into the nanocarrier. The formulations were characterized in terms of particle size, zeta potential and stability over time and micelles performance on the skin was evaluated through the quantification of imiquimod retention in the skin layers and the visualization of a micelle-loaded fluorescent dye by two-photon microscopy. The results showed that imiquimod solubility strictly depends on the nature and concentration of the co-encapsulated compounds. The micellar formulation based on TPGS and oleic acid was identified as the most interesting in terms of both drug solubility (which was increased from few µg/mL to 1154.01 ± 112.78 µg/mL) and micellar stability (which was evaluated up to 6 months from micelles preparation). The delivery efficiency after the application of this formulation alone or incorporated in hydrogels showed to be 42- and 25-folds higher than the one of the commercial creams.

Expanding the Chemical Space of Benzimidazole Dicationic Ionic Liquids

Benzimidazole dicationic ionic liquids (BDILs) have not yet been widely explored in spite of their potential. Therefore, two structurally related families of BDILs, paired with either bromide or bistriflimide anions and bearing alkyl spacers ranging from C3 to C6, have been prepared. Their thermal properties have been studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), while their electrical properties have been assessed by cyclic voltammetry (CV). TG analysis confirmed the higher stability of the bistriflimide BDILs over the bromide BDILs, with minor variation within the two families. Conversely, DSC and CV allowed for ascertaining the role played by the spacer length. In particular, the thermal behavior changed dramatically among the members of the bistriflimide family, and all three possible thermal behavior types of ILs were observed. Furthermore, cyclic voltammetry showed different electrochemical window (C3(C1BenzIm)2/2Tf2N < C4(C1BenzIm)2/2Tf2N, C5(C1BenzIm)2/2Tf2N < C6(C1BenzIm)2/2Tf2N) as well as a reduction peak potential, shape, and intensity as a function of the spacer length. The results obtained highlight the benefit of accessing a more structurally diverse pool of compounds offered by dicationic ILs when compared to the parent monocationic ILs. In particular, gains are to be found in the ease of fine-tuning their properties, which translates in facilitating further investigations toward BDILs as designer solvents and catalysts.

Influence of Small Quantities of Water on the Physical Properties of Alkylammonium Nitrate Ionic Liquids

This paper presents a comprehensive study of two alkylammonium nitrate ionic liquids. As part of this family of materials, mainly ethylammonium nitrate (EAN) and also propylammonium nitrate (PAN) have attracted a great deal of attention during the last decades due to their potential applications in many fields. Although there have been numerous publications focused on the measurement of their physical properties, a great dispersion can be observed in the results obtained for the same magnitude. One of the critical points to be taken into account in their physical characterization is their water content. Thus, the main objective of this work was to determine the degree of influence of the presence of small quantities of water in EAN and PAN on the measurement of density, viscosity, electrical conductivity, refractive index and surface tension. For this purpose, the first three properties were determined in samples of EAN and PAN with water contents below 30,000 ppm in a wide range of temperatures, between 5 and 95 °C, while the last two were obtained at 25 °C. As a result of this study, it has been concluded that the presence of water is critical in those physical properties that involve mass or charge transport processes, resulting in the finding that the absolute value of the average percentage change in both viscosity and electrical conductivity is above 40%. Meanwhile, refractive index (≤0.3%), density (≤0.5%) and surface tension (≤2%) present much less significant changes.

Employing Drug Delivery Strategies to Overcome Challenges Using TLR7/8 Agonists for Cancer Immunotherapy

Toll-like receptors (TLRs) are a potential target for cancer immunotherapy due to their role in the activation of the innate immune system. More specifically, TLR7 and TLR8, two structurally similar pattern recognition receptors that trigger interferon and cytokine responses, have proven to be therapeutically relevant targets for cancer in numerous preclinical and clinical studies. When triggered by an agonist, such as imiquimod or resiquimod, the TLR7/8 activation pathway induces cellular and humoral immune responses that can kill cancer cells with high specificity. Unfortunately, TLR7/8 agonists also present a number of issues that must be overcome prior to broad clinical implementation, such as poor drug solubility and systemic toxic effects. To overcome the key limitations of TLR7/8 agonists as a cancer therapy, biomaterial-based drug delivery systems have been developed. These delivery devices are highly diverse in their design and include systems that can be directly administered to the tumor, passively accumulated in relevant cancerous and lymph tissues, triggered by environmental stimuli, or actively targeted to specific physiological areas and cellular populations. In addition to improved delivery systems, recent studies have also demonstrated the potential benefits of TLR7/8 agonist co-delivery with other types of therapies, particularly checkpoint inhibitors, cancer vaccines, and chemotherapeutics, which can yield impressive anti-cancer effects. In this review, we discuss recent advances in the development of TLR7/8 agonist delivery systems and provide perspective on promising future directions.

Local Chemotherapy as an Adjuvant Treatment in Unresectable Squamous Cell Carcinoma: What Do We Know So Far?

Background: Squamous cell carcinoma (SCC) is one of the most common cancers involving skin and oral mucosa. Although this condition's gold-standard treatment is the surgical removal of the lesions, the physician must propose alternative treatments in some cases due to the patient's ineligibility for surgery. Among the available alternative therapies, local chemotherapy may represent an initial treatment in combination with radiotherapy or systemic chemotherapy due to the low frequency of side-effects and the lack of necessity for expensive devices. Methods: In this paper, we review all available literature in various databases (PubMed, Scopus-Embase, Web of Science), proposing local chemotherapy as a treatment for cutaneous and oral SCC. Exclusion criteria included ocular lesions (where topical treatments are common), non-English language, and non-human studies. Results: We included 14 studies in this review. The majority were case reports and case series describing the treatment of non-resectable localized SCC with either imiquimod or 5-fluorouracil. We also analyzed small studies proposing combination treatments. Almost all studies reported an excellent clinical outcome, with a low risk of relapses in time. Conclusions: Resection of the lesion remains the gold-standard treatment for SCC. When this approach is not feasible, local chemotherapy may represent a treatment alternative, and it may also be associated with radiotherapy or systemic chemotherapy.

Outperformance in Acrylation: Supported D-Glucose-Based Ionic Liquid Phase on MWCNTs for Immobilized Lipase B from Candida antarctica as Catalytic System

This study presents a highly efficient method of a synthesis of n-butyl acrylate via esterification of acrylic acid and n-butanol in the presence of supported ionic liquid phase (SILP) biocatalyst consisting of the lipase B from Candida antarctica (CALB) and multi-walled carbon nanotubes (MWCNTs) modified by D-glucose-based ionic liquids. Favorable reaction conditions (acrylic acid: n-butanol molar ratio 1:2, cyclohexane as a solvent, biocatalyst 0.150 g per 1 mmol of acrylic acid, temperature 25 °C) allowed the achievement of a 99% yield of n-butyl acrylate in 24 h. Screening of various ionic liquids showed that the most promising result was obtained if N-(6-deoxy-1-O-methoxy-α-D-glucopyranosyl)-N,N,N-trimethylammonium bis-(trifluoromethylsulfonyl)imide ([N(CH3)3GlcOCH3][N(Tf)2]) was selected in order to modify the outer surface of MWCNTs. The final SILP biocatalyst-CNTs-[N(CH3)3GlcOCH3][N(Tf)2]-CALB contained 1.8 wt.% of IL and 4.2 wt.% of CALB. Application of the SILP biocatalyst led to the enhanced activity of CALB in comparison with the biocatalyst prepared via physical adsorption of CALB onto MWCNTs (CNTs-CALB), as well as with commercially available Novozyme 435. Thus, the crucial role of IL in the stabilization of biocatalysts was clearly demonstrated. In addition, a significant stability of the developed biocatalytic system was confirmed (three runs with a yield of ester over 90%).

Topical 5% Imiquimod Sequential to Surgery for HPV-Related Squamous Cell Carcinoma of the Lip

Background: Squamous cell carcinoma (SCC) is one of the most common neoplasms affecting the oral cavity and the face. Its more differentiated forms may be associated with human papilloma virus (HPV) infection. Case report: In this paper, we report the case of an 86-year-old patient with a well-differentiated SCC of the lower lip associated with HPV treated with surgery with a non-complete histological resolution. Imiquimod 5% cream was applied on the surgical scar once a day for two weeks and then once a week. Two years after SCC removal, no relapse has occurred. Conclusions: Topical imiquimod may be a safe and effective treatment after surgery in SCC of the oral area to reduce the risk of relapses.

Ionic Liquid-Enabled Topical Delivery of Immunomodulators

Skin is one of the most immunologically active organs of the body due to the presence of diverse immune cells and its active involvement in the innate and adaptive immunity. Because of its unique location and immunological role, skin offers an excellent site for the introduction of immunomodulators to synergize with the active immune microenviroment for the desired outcome. However, delivery of immunomodulators to the skin remains a significant challenge due to the skin's barrier properties. Here, we report an ionic liquid (IL)-based strategy to formulate and deliver immunomodulators to the skin. Using imiquimod (IMQ) and triamcinolone acetonide (TCA) as the respective model immunoactive and immunosuppressive drugs, we demonstrated that ILs significantly enhanced the solubility of immunomodulators. In addition, ILs enabled the formulation of the immunomodulators into stable, topically applicable forms. Our ex vivo skin penetration studies revealed that the IL formulations outperformed respective commercial topical comparators and delivered significantly more immunomodulators to deep skin layers. The lead IMQ formulation exhibited >10-fold better efficacy in delivering IMQ to the deep skin layers as compared to the commercial 5% IMQ cream. Lead TCA formulations achieved a dose level in deep skin layers that is comparable to that by clinically used intralesional injections. Our data collectively suggest that the IL-based strategy can be a simple and effective platform for delivery of immunomodulators to the skin.

Sugar-Based Ionic Liquids: Multifaceted Challenges and Intriguing Potential

Carbohydrates represent a promising option in transitioning from oil-based chemical resources to renewable ones, with the goal of developing chemistries for a sustainable future. Cellulose, hemicellulose, and largely available monosaccharides already provide useful chemical building blocks, so-called platform chemicals, such as levulinic acid and hydroxymethyl furfural, as well as solvents like cyrene or gamma-valerolactone. Therefore, there is great anticipation for novel applications involving materials and chemicals derived from sugars. In the field of ionic liquids (ILs), sugar-based ILs have been overlooked for a long time, mainly on account of their multistep demanding preparation. However, exploring new strategies for accessing sugar-based ILs, their study, and their exploitation, are attracting increasing interest. This is due to the growing concerns about the negative (eco)toxicity profile of most ILs in conjunction with their non-sustainable nature. In the present review, a literature survey concerning the development of sugar-based ILs since 2011 is presented. Their preparation strategies and thermal behavior analyses, sorted by sugar type, make up the first two sections with the intention to provide the reader with a useful guide. A final overview of the potential applications of sugar-based ILs and their future perspectives complement the present analysis.

Insight into the Liquid–Liquid Extraction System AuCl4−/HCl/A327H+Cl− Ionic Liquid/Toluene

The ionic liquid A327H+Cl− is generated by reaction of the tertiary amine A327 (industrial mixture of tri-octyl and tri-decyl amines) and hydrochloric acid solutions. In this study, the extraction of Au(III) by A327H+Cl− ionic liquid under various variables, including metal and ionic liquid concentrations, was investigated. Results indicate that A327H+AuCl4− is formed by an exothermic (ΔH° = −3 kJ/mol) reaction in the organic solution. Aqueous ionic strength influences the formation constant values, and the specific interaction theory (SIT) was used to estimate the interaction coefficient between AuCl4− and H+. Gold (III) was stripped using thiocyanate media, and from the strip solutions, gold was precipitated as gold nanoparticles.

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].

Facile and Rapid Isolation of Oxypeucedanin Hydrate and Byakangelicin from Angelica dahurica by Using [Bmim]Tf2N Ionic Liquid

Ionic liquids (ILs) have sparked much interest as alternative solvents for plant materials as they provide distinctive properties. Therefore, in this study, the capacity of ILs to extract oxypeucedanin hydrate and byakangelicin from the roots of Angelica dahurica (A. dahurica) was investigated. The back-extraction method was examined to recover target components from the IL solution as well. Herein, [Bmim]Tf2N demonstrated outstanding performance for extracting oxypeucedanin hydrate and byakangelicin. Moreover, factors including solvent/solid ratio, extraction temperature and time were investigated and optimized using a statistical approach. Under optimum extraction conditions (solvent/solid ratio 8:1, temperature 60 °C and time 180 min), the yields of oxypeucedanin hydrate and byakangelicin were 98.06% and 99.52%, respectively. In addition, 0.01 N HCl showed the most significant ability to back-extract target components from the [Bmim]Tf2N solution. The total content of both oxypeucedanin hydrate (36.99%) and byakangelicin (45.12%) in the final product exceeded 80%. Based on the data, the proposed approach demonstrated satisfactory extraction ability, recovery and enrichment of target compounds in record time. Therefore, the developed approach is assumed essential to considerably reduce drawbacks encountered during the separation of oxypeucedanin hydrate and byakangelicin from the roots of A. dahurica.

Combination of Nanomicellar Technology and In Situ Gelling Polymer as Ocular Drug Delivery System (ODDS) for Cyclosporine-A

A combination of in situ gelling systems and a loaded drug self-assembling nanomicellar carrier was chosen in this study as a new potential Ocular Drug Delivery System (ODDS) for Cyclosporine-A (CyA), a poorly water-soluble drug. Two non-ionic surfactants (d-α-tocopherol polyethylene glycol succinate, VitE-TPGS and polyoxyl 40 hydrogenated castor oil, RH-40) were used to produce the nanomicelles. The physical-chemical characterization of the nanomicelles in terms of CyA entrapment (EE%) and loading efficiency (LE%), cloud point (CP), regeneration time (RT), size and polydispersity index (PI) allowed us to select the best combination of surfactant mixture, which showed appropriate stability, high CyA-EE (99.07%), very small and homogeneous dimensions and favored the solubilization of an amount of CyA (0.144% w/w) comparable to that contained in marketed emulsion Ikervis^®. The selected nanomicellar formulation incorporated into optimized ion-sensitive polymeric dispersions of gellan gum (GG-LA: 0.10, 0.15 and 0.20% w/w) able to trigger the sol-gel transition after instillation was characterized from technological (osmolality, pH, gelling capacity, rheological behavior, wettability, TEM and storage stability at 4 and 20 °C) and biopharmaceutical points of view. This new combined approach allowed us to obtain clear aqueous dispersions that were easy to instill and able to form a viscous gel when in contact with the tear fluid, improving CyA ocular bioavailability. Furthermore, this new ODDS prevented CyA transcorneal permeation, exhibited low cytotoxicity and prolonged the CyA resident time in the precorneal area compared to Ikervis^®.