Are Myths and Preconceptions Preventing us from Applying Ionic Liquid Forms of Antiviral Medicines to the Current Health Crisis?

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.

A Comparison of Spray-Drying and Co-Precipitation for the Generation of Amorphous Solid Dispersions (ASDs) of Hydrochlorothiazide and Simvastatin

Co-processing of APIs, the practice of creating multi-component APIs directly in chemical processing facilities used to make drug substance, is gaining increased attention with a view to streamlining manufacturing, improving supply chain robustness and accessing enhanced product attributes in terms of stability and bioavailability. Direct co-precipitation of amorphous solid dispersions (ASDs) at the final step of chemical processing is one such example of co-processing. The purpose of this work was to investigate the application of different advanced solvent-based processing techniques - direct co-precipitation (CP) and the benchmark well-established spray-drying (SD) process - to the production of ASDs comprised of a drug with a high T_g (hydrochlorothiazide, HCTZ) or a low T_g (simvastatin, SIM) molecularly dispersed in a PVP/VA 64 or Soluplus® matrix. ASDs of the same composition were manufactured by the two different methods and were characterised using powder X-ray diffraction (PXRD), modulated differential scanning calorimetry (mDSC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). Both methods produced ASDs that were PXRD amorphous, with some differences, depending on the process used, in glass transition temperature and particle size distribution. Irrespective of manufacturing method used, all ASDs remained PXRD amorphous when subjected to high relative humidity conditions (75% RH, 25°C) for four weeks, although changes in the colour and physical characteristics were observed on storage for spray-dried systems with SIM and PVP/VA 64 copolymer. The particle morphology differed for co-precipitated compared to spray dried systems, with powder generated by the former process being comprised of more irregularly shaped particles of larger particle size when compared to the equivalent spray-dried systems which may enable more streamlined drug product processes to be used for CP materials. These differences may have implications in downstream drug product processing. A limitation identified when applying the solvent/anti-solvent co-precipitation method to SIM was the high antisolvent to solvent ratios required to effect the precipitation process. Thus, while similar outcomes may arise for both co-precipitation and spray drying processes in terms of ASD critical quality attributes, practical implications of applying the co-precipitation method and downstream processability of the resulting ASDs should be considered when choosing one solvent-based ASD production process over another.

Improving the Antimycobacterial Drug Clofazimine through Formation of Organic Salts by Combination with Fluoroquinolones

This work reports the synthesis, structural and thermal analysis, and in vitro evaluation of the antimicrobial activity of two new organic salts (OSs) derived from the antimycobacterial drug clofazimine and the fluoroquinolones ofloxacin or norfloxacin. Organic salts derived from active pharmaceutical ingredients (API-OSs), as those herein disclosed, hold promise as cost-effective formulations with improved features over their parent drugs, thus enabling the mitigation of some of their shortcomings. For instance, in the specific case of clofazimine, its poor solubility severely limits its bioavailability. As compared to clofazimine, the clofazimine-derived OSs now reported have improved solubility and thermostability, without any major deleterious effects on the drug's bioactivity profile.

Ecotoxicity of binary mixtures of ILs and inorganic salts of electrochemical interest

The applicability of ionic liquids (ILs) has increased over the last years, and even new opportunities are becoming a reality, i.e. mixtures of pure IL and inorganic salt as electrolytes for smart electrochemical devices, yet the effects on the environment are almost unknown. In this work, the ecotoxicity of two pure protic ILs (Ethylammonium nitrate and Ethylimidazolium nitrate) and two pure aprotic ILs (butylmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide and butyldimethylimidazolium bis(trifluoromethylsulfonyl)imide) and that of their binary mixtures with inorganic salts with common cation was tested towards changes in the bioluminescence of the bacteria Aliivibrio fischeri, using the Microtox® standard toxicity test. EC₅₀ of these mixtures was determined over three standard periods of time and compared with the corresponding values to pure ILs. Results indicate that the aprotic ILs are more toxic than protic and that aromatic are more toxic than non-aromatic. The addition of inorganic mono (LiNO₃), di (Ca(NO₃)₂·4H₂O, Mg(NO₃)₂·6H₂O) and trivalent (Al(NO₃)₃·9H₂O) salts in binary mixtures with EAN was analysed first. The latter was found to induce an important increase in toxicity. Finally, mixtures of IL-inorganic lithium salt (LiNO₃, for the protic ILs and LiTFSI for the aprotic ILs) toxicity was also studied, which showed toxicity levels strongly dependent on the IL of the mixture.

Docusate-Based Ionic Liquids of Anthelmintic Benzimidazoles Show Improved Pharmaceutical Processability, Lipid Solubility, and in Vitro Activity against Cryptococcus neoformans

As the existing therapeutic modalities for the treatment of cryptococcal meningitis (CM) have suboptimal efficacy, repurposing existing drugs for the treatment of CM is of great interest. The FDA-approved anthelmintic benzimidazoles, albendazole, mebendazole, and flubendazole, have demonstrated potent but variable in vitro activity against Cryptococcus neoformans, the predominant fungal species responsible for CM. We performed molecular docking studies to ascertain the interaction of albendazole, mebendazole, and flubendazole with a C. neoformans β-tubulin structure, which revealed differential binding interactions and explained the different in vitro efficacies reported previously and observed in this investigation. Despite their promising in vitro efficacy, the repurposing of anthelmintic benzimidazoles for oral CM therapy is significantly hampered due to their high crystallinity, poor pharmaceutical processability, low and pH-dependent solubility, and drug precipitation upon entering the intestine, all of which result in low and variable oral bioavailability. Here, we demonstrate that the anthelmintic benzimidazoles can be transformed into partially amorphous low-melting ionic liquids (ILs) with a simple metathesis reaction using amphiphilic sodium docusate as a counterion. In vitro efficacy studies on a laboratory reference and a clinical isolate of C. neoformans showed 2- to 4-fold lower IC₉₀ values for docusate-based ILs compared to the pure anthelmintic benzimidazoles. Furthermore, using a C. neoformans strain with green fluorescent protein (GFP)-tagged β-tubulin and albendazole and its docusate IL as model candidates, we showed that the benzimidazoles and their ILs reduce the viability of C. neoformans by interfering with its microtubule assembly. Unlike pure anthelmintic benzimidazoles, the docusate-based ILs showed excellent solubility in organic solvents and >30-fold higher solubility in bioavailability-enhancing lipid vehicles. Finally, the docusate ILs were successfully incorporated into SoluPlus, a self-assembling biodegradable polymer, which upon dilution with water formed polymeric micelles with a size of <100 nm. Thus, the development of docusate-based ILs represents an effective approach to improve the physicochemical properties and potency of anthelmintic benzimidazoles to facilitate their repurposing and preclinical development for CM therapy.

Tri-tert-butyl(n-alkyl)phosphonium Ionic Liquids: Structure, Properties and Application as Hybrid Catalyst Nanomaterials

A series of sterically hindered tri-tert-butyl(n-alkyl)phosphonium salts (n-CnH2n+1 with n = 1, 3, 5, 7, 9, 11, 13, 15, 17) was synthesized and systematically studied by 1H, 13C, 31P NMR spectroscopy, ESI-MS, single-crystal X-ray diffraction analysis and melting point measurement. Formation and stabilization palladium nanoparticles (PdNPs) were used to characterize the phosphonium ionic liquid (PIL) nanoscale interaction ability. The colloidal Pd in the PIL systems was described with TEM and DLS analyses and applied in the Suzuki cross-coupling reaction. The PILs were proven to be suitable stabilizers of PdNPs possessing high catalytic activity. The tri-tert-butyl(n-alkyl)phosphonium salts showed a complex nonlinear correlation of the structure–property relationship. The synthesized family of PILs has a broad variety of structural features, including hydrophobic and hydrophilic structures that are entirely expressed in the diversity of their properties

Surfing the Third Wave of Ionic Liquids: A Brief Review on the Role of Surface-Active Ionic Liquids in Drug Development and Delivery

The relevance of ionic liquids (ILs) is now well established in many fields, as their unique properties make them appealing as 1) greener alternatives to organic solvents (first-generation ILs), 2) tunable task-specific materials (second-generation ILs), and 3) multifunctional players in life and pharmaceutical sciences (third-generation ILs). This third wave of ILs encompasses a wide range of compounds, from bioactive molecules with single or even dual therapeutic action, to potential ingredient molecules for drug formulation and transport systems. In this context, the focus of this review is the emergent role of surface-active ionic liquids (SAILs) in drug development and delivery.

Misinformation About COVID-19 in Sub-Saharan Africa: Evidence from a Cross-Sectional Survey

Misinformation about coronavirus disease 2019 (COVID-19) is a significant threat to global public health because it can inadvertently exacerbate public health challenges by promoting spread of the disease. This study used a convenience sampling technique to examine factors associated with misinformation about COVID-19 in sub-Saharan Africa using an online cross-sectional survey. A link to the online self-administered questionnaire was distributed to 1,969 participants through social media platforms and the authors' email networks. Four false statements-informed by results from a pilot study-were included in the survey. The participants' responses were classified as "Agree," "Neutral," and "Disagree." A multinomial logistic regression was used to examine associated factors. Among those who responded to the survey, 19.3% believed that COVID-19 was designed to reduce world population, 22.2% thought the ability to hold your breath for 10 seconds meant that you do not have COVID-19, 27.8% believed drinking hot water flushes down the virus, and 13.9% thought that COVID-19 had little effect on Blacks compared with Whites. An average of 33.7% were unsure whether the 4 false statements were true. Multivariate analysis revealed that those who thought COVID-19 was unlikely to continue in their countries reported higher odds of believing in these 4 false statements. Other significant factors associated with belief in misinformation were age (older adults), employment status (unemployed), gender (female), education (bachelor's degree), and knowledge about the main clinical symptoms of COVID-19. Strategies to reduce the spread of false information about COVID-19 and other future pandemics should target these subpopulations, especially those with limited education. This will also enhance compliance with public health measures to reduce spread of further outbreaks.

Sterically Hindered Phosphonium Salts: Structure, Properties and Palladium Nanoparticle Stabilization

A new family of sterically hindered alkyl(tri-tert-butyl) phosphonium salts (n-CnH2n+1 with n = 2, 4, 6, 8, 10, 12, 14, 16, 18, 20) was synthesized and evaluated as stabilizers for the formation of palladium nanoparticles (PdNPs), and the prepared PdNPs, stabilized by a series of phosphonium salts, were applied as catalysts of the Suzuki cross-coupling reaction. All investigated phosphonium salts were found to be excellent stabilizers of metal nanoparticles of small catalytically active size with a narrow size distribution. In addition, palladium nanoparticles exhibited exceptional stability: the presence of phosphonium salts prevented agglomeration and precipitation during the catalytic reaction.

Recycling Old Antibiotics with Ionic Liquids

Antibiotics are considered one of the great “miracles” of the 20th century. Now in the 21st century in the post-antibiotic era, the miracle is turning into a nightmare, due to the growing problem of the resistance of microorganisms to classic antimicrobials and the non-investment by the pharmaceutical industry in new antimicrobial agents. Unfortunately, the current COVID-19 pandemic has demonstrated the global risks associated with uncontrolled infections and the various forms of impact that such a pandemic may have on the economy and on social habits besides the associated morbidity and mortality. Therefore, there is an urgent need to recycle classic antibiotics, as is the case in the use of ionic liquids (ILs) based on antibiotics. Thus, the aim of the present review is to summarize the data on ILs, mainly those with antimicrobial action and especially against resistant strains. The main conclusions of this article are that ILs are flexible due to their ability to modulate cations and anions as a salt, making it possible to combine the properties of both and multiplying the activity of separate cations and anions. Also, these compounds have low cost methods of production, which makes it highly attractive to explore them, especially as antimicrobial agents and against resistant strains. ILs may further be combined with other therapeutic strategies, such as phage or lysine therapy, enhancing the therapeutic arsenal needed to fight this worldwide problem of antibacterial resistance. Thus, the use of ILs as antibiotics by themselves or together with phage therapy and lysine therapy are promising alternatives against pathogenic microorganisms, and may have the possibility to be used in new ways in order to restrain uncontrolled infections.