Interfacial and antibacterial properties of imidazolium based ionic liquids having different counterions with ciprofloxacin

The study of active pharmaceutical ingredients (API) with ionic liquids (ILs) becomes a significant research area for pharmaceutical industry. Thus, the present study aims to study the physicochemical and biological behaviour of ionic liquids having different counter ions in presence of an antibacterial drug, ciprofloxacin (CIP). The interaction of CIP with ILs, 1-decyl-3-methylimidazolium tetrafluoroborate [C10mim][BF4], 1-decyl-3-methylimidazolium bromide [C10mim][Br], and 1-decyl-3-methylimidazolium chloride [C10mim][Cl] has been studied by utilising surface tension, conductivity and DLS techniques. The various interfacial and thermodynamic properties of pure ILs and their complexes with CIP have been investigated from surface tension data. The thermodynamic data thus obtained suggested that the interaction between ILs and CIP was spontaneous. The dynamic light scattering (DLS) measurement showed that the aggregates size of ILs increases in presence of CIP. The complexation of ILs and drug was further confirmed by zeta potential measurement. The combined analysis suggested that the drug molecules is solubilized within the micellar core of ILs due to hydrophobic interaction, however, few molecules reside in the upper palisade layer of micelle-water interface. In addition, we have also investigated the antibacterial activity of individual ILs and CIP against two clinically relevant microorganism, E. coli and S. aureus. The effect of ILs on antibacterial activity of CIP was determined against E. coli and S. aureus and results showed the remarkable improvement in the activity of CIP in the presence of imidazolium ILs. The maximum reduction in MIC was found in presence of [C10mim][BF4] was found as compared to [C10mim][Br]/[Dmim][Cl]. The results of the current study showed the importance of ILs in pharmaceutical industries