Effect of imidazolium-based ionic liquid on the antibacterial activity of an expired drug rifampicin

Transdermal Insulin Delivery Using Ionic Liquid-Mediated Nanovesicles for Diabetes Treatment

Transdermal insulin delivery is a promising method for diabetes management, providing the potential for controlled, sustained release and prolonged insulin effectiveness. However, the large molecular weight of insulin hinders its passive absorption through the stratum corneum (SC) of the skin, and high doses of insulin are required, which limits the commercial viability. We developed ethosome (ET) and trans-ethosome (TET) nanovesicle formulations containing a biocompatible lipid-based ionic liquid, [EDMPC][Lin], dissolved in 35% ethanol. TET formulations were obtained by adding isopropyl myristate (IPM), Tween-80, or Span-20 as surfactants to ET formulations. Dynamic light scattering, ζ-potential, transmission electron microscopy, and confocal laser scanning microscopy studies revealed that the nanovesicles had a stable particle size. The formulations remained stable at 4 °C for more than 3 months. ET and TET formulations containing IPM (TET1) significantly (p < 0.0001) enhanced the transdermal penetration of FITC-tagged insulin (FITC-Ins) in both mouse and pig skin, compared with that of the control FITC-Ins solution and other TET formulations, by altering the molecular structure of the SC layer. These nanovesicles were found to be biocompatible and nonirritants (cell viability >80%) in the in vitro and in vivo studies on three-dimensional (3D) artificial human skin and a diabetic mouse model, respectively. The ET and TET1 formulations were applied to the skin of diabetic mice at an insulin dosage of 30 IU/kg. The nanovesicle formulations significantly reduced blood glucose levels (BGLs) compared with the initial high BGL value (>150 mg/dL). The nanovesicle-treated mice maintained low BGLs for over 15 h, as opposed to only 2 h in the injection group. The ET and TET1 formulations reduced the BGLs by 62 and 34%, respectively, of the initial value. These ET and TET1 formulations have a high potential for use in commercial transdermal insulin patches, enhancing comfort and adherence in diabetes treatment.

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).

Improved Antibacterial Activity of Peptide Nisin with Pyrrole-Based Ionic Liquids Having Bis(trifluoromethylsulfonyl)imide as a Counterion: A Synergistic Approach to Combat Bacterial Infections

Bacterial resistance against antimicrobial drugs is a forthcoming threat to the prevention and treatment of developing bacterial infections. Hence, the development of new antimicrobial therapy or therapeutic drugs is desperately needed. A combination of antibiotics exhibits synergistic antibacterial effects. As the combination approach of antibiotics has always shown better results against pathogens compared to monotherapy with an antibiotic, we focused on creating a new combination that may reduce the chances of strains attaining resistance, consequently lowering the toxicity factor associated with the consumption of high amounts of antibiotics. Nisin, a food preservative and potential antibiotic, shows antibacterial activity against Gram-positive strains. Since the past decade, ionic liquids (ILs) have proven to be an important class of potential antibacterial agents. In our study, we studied the effect of pyrrolidinium-based ILs and arrived at a noncovalent conjugate formed by combining nisin with ILs. The conjugates were tested against a couple of clinically relevant microorganisms, namely, Escherichia coli and Staphylococcus aureus. We reached a novel discovery that the combination of sodium/iodide symporter (NIS) and IL exhibited inhibitory effects against Gram-negative bacteria, which was not observed with NIS alone. The results showed remarkable improvement in the minimum inhibitory concentration (MIC) value of NIS in the presence of ILs targeted against both microorganisms. Further, flow cytometry and confocal microscopy results revealed the membrane disruption efficiency of the best combination obtained, leading to cell death. Additionally, the complexation of nisin and ILs was studied using various techniques, such as surface tension, dynamic light scattering, absorption spectroscopy, and molecular docking.

Imidazolium-Based Ionic Liquid-Assisted Silver Nanoparticles and Their Antibacterial Activity: Experimental and Density Functional Theory Studies

The exclusive properties of ionic liquids (ILs) offer various opportunities to develop advanced materials with appreciable therapeutic applications. Imidazolium-based ILs have been frequently used as reaction media and stabilizers for the development and surface functionalization of noble metal nanoparticles (NPs). This study reports the citrate-mediated reduction of silver ions in three different ILs, that is, 1-ethyl-3-methylimidazolium methyl sulfate ([EMIM][MS]), 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM][OTf]), and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][TFSI]). The resulting Ag-ILs NPs were characterized using many analytical techniques, including UV-visible spectroscopy, dynamic light scattering (DLS), scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction (XRD). DLS and XRD characterization revealed the negatively charged Ag-[EMIM][MS] NPs, Ag-[BMIM][OTf] NPs, and Ag-[BMIM][TFSI] NPs with mean hydrodynamic sizes of 278, 316, and 279 nm, respectively, and a face-centered cubic structure. These hybrid nanomaterials were subjected to in vitro antibacterial screening against three bacterial strains. The Ag-[BMIM][OTf] NPs exhibited significant activities against Escherichia coli, Staphylococcus aureus, and Enterobacter cloacae. The lowest inhibition concentration of 62.5 μg/mL was recorded against E. coli using Ag-[EMIM][MS] and Ag-[BMIM][OTf] NPs. Further, the density functional theory calculations carried out on the computed Ag-ILs in the gas phase and water showed relatively stable systems. Ag-[BMIM][TFSI] exhibited the lowest Gibbs free energy change of -34.41 kcal/mol. The value of the global electrophilicity index (ω = 0.1865 eV) for the Ag-[BMIM][OTf] correlated with its good antibacterial activity.

A comparative evaluation of antibacterial activities of imidazolium-, pyridinium-, and phosphonium-based ionic liquids containing octyl side chains

Antibacterial activity is an essential property of ionic liquids. In this work, a comprehensive study has been performed on the antibacterial activity of ionic liquids to be utilized for further research and applications. Eighteen ionic liquids viz. Octyl Imidazolium, octyl Pyridinium, quaternary phosphonium-based cations containing bromide, sodium methane sulphonates, bis(trifluoromethane sulfonyl) imide, dichloroacetate, tetrafluoroborate, hydrogen sulfate were prepared and characterized with the help of different spectroscopic techniques. All these samples of ionic liquids were tested for their antibacterial activity against the most commonly occurring bacteria in the environment, i.e., Enterobacter aerogenes (E. aerogenes), Proteus vulgaris (P. vulgaris), Klebsiella pneumoniae (K. pneumoniae), Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), and Streptococcus pyogenes (S. pyogenes). Most of the ionic liquids show good antibacterial properties, and imidazolium-based ionic liquids were even more antibacterial as compared to positive control. It was observed that a unique combination of cation and anion is essential to achieve desired antibacterial properties. The mechanism of antibacterial activity was further investigated using density functional theory calculations. A good correlation was found between experimental and theoretical studies.