Composition and Concentration Gradient Induced Structural Transition from Micelles to Vesicles in the Mixed System of Ionic Liquid-Diclofenac Sodium

Interaction and antibacterial activity of ciprofloxacin with choline based ionic liquid and CTAB: A comparative spectroscopic study

In this study, the complexation of potential chemo-therapeutic antibacterial drug, ciprofloxacin (CIP) with varying concentrations of surface active compounds (SACs) i.e., (N-(2-hydroxyethyl)-N,N-dimethyl-1-dodecanaminium bromide (12Cho.Br) and cetyltrimethylammonium bromide (CTAB) has been studied. Multispectroscopic techniques were exploited to carry out the study. The higher binding constant (Kb) value for CIP-CTAB than CIP-12Cho.Br obtained from fluorescence data revealed stronger binding of CTAB than 12Cho.Br, owing to the stronger hydrophobic-hydrophobic interaction betweeen CIP and CTAB compared to CIP and 12Cho.Br. The time resolve fluorescence decay shows changes in average lifetime (τavg) with the increasing concentration of 12Cho.Br and CTAB. The changes in τavg suggests that complex formation is taking place between CIP and 12Cho.Br / CTAB. Further, the formation of micelles by 12Cho.Br / CTAB and the effect of alkyl chain length was studied by dynamic light scattering (DLS) and zeta potential to confirm the drug complexation with 12Cho.Br and CTAB. The antibacterial activity has been performed for CIP and 12Cho.Br and CTAB. It was observed that in presence of lower concentrations of 12Cho.Br/ CTAB, the activity of the drug increased. The activity was also found cationic alkyl chain length dependent. Moreover, in-vitro cytotoxicity of CIP and its combinations with 12Cho.Br and CTAB was performed using MTT assay on HEK293 (Human embryonic kidney cells).

Investigating the Influence of Aromatic Counterions on the Micellar Structure and Aggregation Behavior of Morpholinium-Based Surface-Active Ionic Liquids in an Aqueous Solution

Two morpholinium-based surface-active ionic liquids (SAILs) with aromatic counterions were synthesized, namely, n-dodecyl-n-methylmorpholinium salicylate [C12mmor][Sal] and n-dodecyl-n-methylmorpholinium 3-hydroxy-2-naphthoate [C12mmor][3-h-2-n], and explored their aggregation behavior in aqueous solutions systematically. Electrical conductivity, small-angle neutron scattering (SANS), surface tension (ST), and UV-vis spectroscopy measurements were employed to determine various thermodynamic, micellar, and interfacial parameters, like the degree of counterion binding (β), critical micelle concentration (CMC), minimum area per molecule (Amin), surface excess concentration (Γmax), standard Gibbs free energy of adsorption (ΔGad0), aggregation number (Nagg), standard Gibbs free energy of micellization (ΔGm0), standard enthalpy of micelle formation (ΔHm0), and the standard entropy of micellization (ΔSm0) in an aqueous solution. Incorporating the aromatic counterions favors significantly excellent micellization properties over conventional halogenated SAILs such as [C12mmor][Br]. SANS analysis revealed that upon changing the counterion from salicylate to 3-hydroxy-2-naphthoate, the structure changed from prolate ellipsoidal micelles to large unilamellar vesicles. Also, increasing the concentration in the case of [C12mmor][Sal] resulted in a lower aggregation number.

Spectroscopic and DFT study of imidazolium based ionic liquids with broad spectrum antibacterial drug levofloxacin

Herein, we have shown the interaction of levofloxacin (LVF) with two imidazolium based ionic liquids (ILs), 1-butly-3-methylimidazolium chloride ([Bmim][Cl]) and 1-decyl-3-methylimidazolium chloride ([Dmim][Cl]) by utilising spectroscopic techniques along with computational approach. Both [Bmim][Cl] and [Dmim][Cl] quenched the fluorescence emission of LVF suggesting complex formation between ILs and the drug. The steady-state and time-resolve fluorescence studies revealed that the quenching of fluorescence emission of LVF in the presence of [Bmim][Cl] and [Dmim][Cl], which signified the non-fluorescent complex formation between LVF and ILs. The complex formation between LVF and ILs were also validated by the UV-visible spectroscopy method. The cyclic voltammetry (CV) results further suggest the strong interaction between LVF and ILs. The estimated binding constant (K_b) and free energy change (ΔG) parameters shows the substantial binding of LVF with both the ILs and spontaneous in nature. The value suggested that LVF have stronger binding with [Dmim][Cl] than [Bmim][Cl]. Further, in order to support the results classical density functional theory (DFT) model was performed. The DFT calculations were utilized to explore the 3D structure and the molecular orbitals (HOMO and LUMO) of ILs, LVF and their complexes using Gaussian 09 software. The aggregate size (D_h) and zeta potential of ILs and IL-drug complexes were determined by dynamic light scattering (DLS) and zeta potential in aqueous medium.

Amphiphilic Ionic Liquids Capable to Formulate Organized Systems in an Aqueous Solution, Designed by a Combination of Traditional Surfactants and Commercial Drugs

The present review describes the state of the art in the conversion of pharmaceutically active ingredients (API) in amphiphilic Ionic Liquids (ILs) as alternative drug delivery systems. In particular, we focus our attention on the compounds generated by ionic exchange and without original counterions which generate different systems in comparison with the simple mixtures. In water, these new amphiphiles show similar or even better properties as surfactants in comparison with their precursors. Cations such as 1-alkyl-3-methyl-imidazolium and anions such as dioctyl sulfosuccinate or sodium dodecyl sulfate appear as the amphiphilic components most studied. In conclusion, this work shows interesting information on several promissory compounds and they appear as an interesting challenge to extend the application of ILs in the medical field.

Advances Brought by Hydrophilic Ionic Liquids in Fields Involving Pharmaceuticals

The negligible volatility and high tunable nature of ionic liquids (ILs) have been the main drivers of their investigation in a wide diversity of fields, among which is their application in areas involving pharmaceuticals. Although most literature dealing with ILs is still majorly devoted to hydrophobic ILs, evidence on the potential of hydrophilic ILs have been increasingly provided in the past decade, viz., ILs with improved therapeutic efficiency and bioavailability, ILs with the ability to increase drugs' aqueous solubility, ILs with enhanced extraction performance for pharmaceuticals when employed in biphasic systems and other techniques, and ILs displaying low eco/cyto/toxicity and beneficial biological activities. Given their relevance, it is here overviewed the applications of hydrophilic ILs in fields involving pharmaceuticals, particularly focusing on achievements and advances witnessed during the last decade. The application of hydrophilic ILs within fields involving pharmaceuticals is here critically discussed according to four categories: (i) to improve pharmaceuticals solubility, envisioning improved bioavailability; (ii) as IL-based drug delivery systems; (iii) as pretreatment techniques to improve analytical methods performance dealing with pharmaceuticals, and (iv) in the recovery and purification of pharmaceuticals using IL-based systems. Key factors in the selection of appropriate ILs are identified. Insights and perspectives to bring renewed and effective solutions involving ILs able to compete with current commercial technologies are finally provided.

Role of Hydrotropes in Sparingly Soluble Drug Solubilization: Insight from a Molecular Dynamics Simulation and Experimental Perspectives

Drug molecules' therapeutic efficacy depends on their bioavailability and solubility. But more than 70% of the formulated drug molecules show limited effectiveness due to low water solubility. Thus, the water solubility enhancement technique of drug molecules becomes the need of time. One such way is hydrotropy. The solubilizing agent of a hydrophobic molecule is generally referred to as a hydrotrope, and this phenomenon is termed hydrotropy. This method has high industrial demand, as hydrotropes are noninflammable, readily available, environmentally friendly, quickly recovered, cost-effective, and not involved in solid emulsification. The endless importance of hydrotropes in industry (especially in the pharmaceutical industry) motivated us to prepare a feature article with a clear introduction, detailed mechanistic insights into the hydrotropic solubilization of drug molecules, applications in pharma industries, and some future directions of this technique. Thus, we believe that this feature article will become an adequate manual for the pharmaceutical researchers who want to explore all of the past perspectives of the hydrotropic action of hydrotropes in pharmaceutics.

Ionic Liquids for Therapeutic and Drug Delivery Applications

BACKGROUND

Ionic liquids (ILs) are ionic compounds with highly tunable and remarkable properties which make them an important candidate in multiple domains such as extraction, synthesis, analytics, catalysis, biotechnology, therapeutics as well as pharmaceutical sciences.

OBJECTIVE

This review systematically highlights the classification, properties and toxicity of ionic liquids. It focuses on exploring the biological activity of ionic liquids, which includes antimicrobial and anticancer property along with an emphasis on the concept of Active Pharmaceutical Ingredient- Ionic Liquids (API-ILs) for explaining the emulsifier and solubility enhancement property of ILs. An elaborative discussion on the application of ILs for the development of oral, transdermal and topical drug delivery systems has also been presented with suitable literature support.

CONCLUSION

Ionic liquids possess exceptional potential in the field of medicine, biology and chemistry.

Formation of Drug-Participating Catanionic Aggregates for Extended Delivery of Non-Steroidal Anti-Inflammatory Drugs from Contact Lenses

This paper focuses on extending drug release duration from contact lenses by incorporating catanionic aggregates. The aggregates consist of a long-chain cationic surfactant, i.e., cetalkonium chloride (CKC), and an oppositely charged anti-inflammatory amphiphilic drug. We studied three non-steroidal anti-inflammatory (NSAID) drugs with different octanol–water partition coefficients; diclofenac sodium (DFNa), flurbiprofen sodium (FBNa), and naproxen sodium (NPNa). Confirmation of catanionic aggregate formation in solution was determined by steady and dynamic shear rheology measurements. We observed the increased viscosity, shear thinning, and viscoelastic behavior characteristic of wormlike micelles; the rheological data are reasonably well described using a Maxwellian fluid model with a single relaxation time. In vitro release experiments demonstrated that the extension in the drug release time is dependent on the ability of a drug to form viscoelastic catanionic aggregates. Such aggregates retard the diffusive transport of drug molecules from the contact lenses. Our study revealed that the release kinetics depends on the CKC concentration and the alkyl chain length of the cationic surfactant. We demonstrated that more hydrophobic drugs such as diclofenac sodium show a more extended release than less hydrophobic drugs such as naproxen sodium.

Responsive morphology transition from micelles to vesicles based on dynamic covalent surfactants

A dynamic covalent bond is widely used to fabricate stimuli responsive systems due to its reversible molecular recognition properties. In this study, we developed a pH-responsive morphology transition system based on a mixture of a cationic surfactant CTAB and two nonamphiphilic precursors, 4-hydroxybenzaldehyde (HB) and octylamine (OA), at a molar ratio of 100 : 60 : 60 (CTAB/HB/OA). The morphology transition of CTAB/HB/OA was characterized by 1H NMR spectroscopy, Fourier transform infrared spectroscopy, macroscopic appearance observation, dynamic light scattering, and rheological and cryo-TEM measurements. The phase behavior of CTAB/HB/OA solutions underwent transition from a water-like fluid to a transparent gel-like solution and then converted into a turbid low-viscosity solution upon increasing the pH. Upon increasing the pH from 4.93 to 7.99, the morphology was transformed from spherical micelles to wormlike micelles. Upon further increasing the pH to 12.02, the wormlike micelles gradually disappeared with the formation of vesicles. Thus, a morphology transition from micelles to vesicles can be triggered by varying the pH of CTAB/HB/OA solutions. This drastic variation in morphology behavior was attributed to the pH dependent ionization and formation of the anionic surfactant HB-OA-. Besides, over 3 cycles of morphological alternation among spherical micelles, wormlike micelles and vesicles of the CTAB/HB/OA solutions can be obtained by adjusting the pH.

Bile acid derivative-based catanionic mixtures: versatile tools for superficial charge modulation of supramolecular lamellae and nanotubes

Self-assembled structures formed by mixtures of cationic and anionic surfactants are interesting tools for applications requiring interactions with charged particles and molecules. Nevertheless, they present instability close to the equimolar composition and poor morphological versatility, which is generally restricted to vesicles and micelles. Against this general trend, we report on bile salt derivative based catanionic mixtures assembling in tubules and lamellae depending on the mixture composition. Electrophoretic mobility measurements prove that the composition also dictates their superficial charge, which can be tuned from negative to positive by increasing the positively charged surfactant fraction in the mixtures. The study of the catanionic aggregates was conducted by means of microscopy and spectroscopy techniques and compared to the self-assembly behaviors of the individual building blocks. This study broadens the so far small array of bile salt derivative catanionic systems, confirming their distinctive behavior in the spectrum of catanionic mixtures.

Heteroassembly Ability of Dicationic Ionic Liquids and Neutral Active Pharmaceutical Ingredients

Extensive investigation of interactions and aggregation properties of IL + API systems is necessary to apply ionic liquids (ILs) with different hydrophobic characteristics to drug delivery or in active pharmaceutical ingredient (API) formulations. Therefore, this study aims to investigate the heteroassembly between dicationic ILs ([BisOct(MIM)₂][2X], in which X is Br or BF₄, and [BisOct(BnIM)₂][2Br]), both in the absence and the presence of neutral APIs (salicylic acid, ibuprofen, and paracetamol) with different functional groups. Isothermal titration calorimetry results demonstrate that IL-API associations occur at very low concentrations of IL. These results were reinforced by electrospray ionization mass spectrometry with variable collision-induced dissociation, in which the IL dication interactions with APIs were detected. The strength of the dication-API interaction was determined from E _cm,1/2 data. The aggregation parameters (cac, ΔG _agg ^°, and K) between ILs and APIs were evaluated by conductivity. The ¹H NMR data showed that differences in chemical shifts provided relevant insights about interaction sites in both components.

Aggregation and Morphological Aptitude of Drug-Based Ionic Liquids in Aqueous Solution

Here, we present how replacing the usual inorganic counter ion with a pharmaceutically active aromatic one can greatly affect the interfacial as well as bulk properties of ionic liquids (ILs). We have synthesized a series of novel drug-based ILs, namely, 1-alkyl-3-methylimidazolium diclofenate ([C _n mim][DF]; n = 6, 8, 10, 12, and 14) abbreviated as DF-ILs, wherein DF^- is a well-recognized analgesic and nonsteroidal anti-inflammatory drug. We show strong synergistic interactions between C _n mim⁺ and aromatic DF^- attributed to reduced electrostatic repulsions and increased hydrophobicity from their incorporation, reflecting a 300-fold smaller critical aggregation concentration than that of their Cl^- analogue [C _n mim][Cl]. Interfacial properties for such strongly associating systems are discussed and clearly established to have remarkably improved properties than those of their Cl^- analogues. The decreasing polarity of the cybotactic region of pyrene with increase in the chain length "n" indicates an increased extent of packing of cationic head groups in the Stern layer. DF^- ion seems to play a vital role in the formation of the resulting aggregates, as probed by small angle neutron scattering and transmission electron microscopy. The thermodynamical insights of the aggregation process have been studied using isothermal titration calorimetry and temperature-dependent conductivity experiments. Unilamellar vesicles are formed at extremely low concentration, and also it is the first report that puts into picture the formation of vesicles for [C₆mim][DF] with such a short chain.

Biological Activity of Ionic Liquids and Their Application in Pharmaceutics and Medicine

Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in the form of ionic liquid species. The main aim of this Review is to attract a broad audience of chemical, biological, and medical scientists to study advantages of ionic liquid pharmaceutics. Overall, the discussed data highlight the importance of the research direction defined as "Ioliomics", studies of ions in liquids in modern chemistry, biology, and medicine.

Drug induced micelle-to-vesicle transition in aqueous solutions of cationic surfactants

Solubilization of the drug diclofenac sodium (DS) in micellar aggregates of ionic liquid-based surfactants and cetyltrimethylammonium bromide at 25 °C induces changes to worm-like micelles and vesicles, with potential use in drug delivery.

Probing the Interaction between a DNA Nucleotide (Adenosine-5'-Monophosphate Disodium) and Surface Active Ionic Liquids by Rotational Relaxation Measurement and Fluorescence Correlation Spectroscopy

This article demonstrates the interaction of a deoxyribonucleic acid (DNA) nucleotide, adenosine-5'-monophosphate disodium (AMP) with a cationic surface active ionic liquid (SAIL) 1-dodecyl-3-methylimidazoium chloride (C₁₂mimCl), and an anionic SAIL, 1-butyl-3-methylimidazolium n-octylsulfate ([C₄mim][C₈SO₄]). Dynamic light scattering (DLS) measurements and ¹H NMR (nuclear magnetic resonance) studies indicate that substantial interaction is taking place among the DNA nucleotide (AMP) and the SAILs. Moreover, cryogenic transmission electron microscopy (cryo-TEM) suggests that SAILs containing micellar assemblies are transformed into larger micellar assemblies in the presence of DNA nucleotides. Additionally, the rotational motion of two oppositely charged molecules, rhodamine 6G perchlorate (R6G) and fluorescein sodium salt (Fl-Na), have been monitored in these aggregates. The rotational motion of R6G and Fl-Na differs significantly between SAILs micelles and SAILs-AMP containing larger micellar aggregates. The effect of negatively charged DNA nucleotide (AMP) addition into the cationic and anionic SAILs is more prominent for the cationic charged molecule R6G than that of anionic probe Fl-Na due to the favorable electrostatic interaction between the AMP and cationic R6G. Moreover, the influence of the anionic DNA nucleotide on the cationic and anionic SAIL micelles is monitored through the variation of the lateral diffusion motion of oppositely charged probe molecules (R6G and Fl-Na) inside these aggregates. This variation in diffusion coefficient values also suggests that the interaction pattern of these oppositely charged probes are different within the SAILs-nucleotide containing aggregates. Therefore, both rotational and translational diffusion measurements confirm that the DNA nucleotide (AMP) renders more rigid microenvironment within the micellar solution of SAILs.

Juglone loaded poloxamer 188/phospholipid mixed micelles evaluated in vitro and in vivo in breast cancer

AIM

Investigating the effects of juglone loaded P188/phospholipid mixed micelles (J-MM) in breast cancer.

MATERIALS & METHODS

In vitro cytotoxicity, apoptotic effects, in vivo therapeutic efficacy and toxicity were used to assess its antitumour effect. Uptake and imaging were used to evaluate the effect on the uptake and passive targeting.

RESULTS

Mixed micelle carrier enhanced the targeting and uptake by MB-231 cells. The tumour inhibition rates in tumour xenograft models for paclitaxel, juglone, J-MM (10mg/kg) and J-MM (40mg/kg) were 46%, 27%, 39% and 53%, respectively. J-MM (10mg/kg) exhibited lower toxicity compared with that by free juglone or high dose J-MM.

CONCLUSION

J-MM exhibited low toxicity, improved cellular uptake, passive targeting and anti-cancer effects in breast cancer model.