Ciprofloxacin Molecules Research Articles

Removal of ciprofloxacin from hospital wastewater using electrocoagulation technique by aluminum electrode: Optimization and modelling through response surface methodology

Abstract Pharmaceuticals as severe contaminants of surface and ground water around the manufacturing communities and residential zones received growing attention recently. Since, there is no report on ciprofloxacin (CIP) removal using electrocoagulation (EC) process by aluminum electrodes, the present work deals with efficient removal of CIP from hospital wastewater using mentioned method. Response surface methodology (RSM) was used to evaluate the main effects of parameters, their simultaneous interactions and quadratic effect to achieve the optimum condition for EC process. According to the obtained results from regression analysis, it was found that the experimental data are best fitted to the second-order polynomial model with coefficient of determination (R 2 ) value of 0.9086, adjust correlation coefficient (Adj. R 2 ) value of 0.8796 and predicted correlation coefficient (pred. R 2 ) value of 0.7834. EC process was applied successfully with removal efficiency of 88.57% under optimal operating condition of pH 7.78, inter-electrode distance 1 cm, reaction time 20 min, current density 12.5 mA cm −2 and electrolyte dose of 0.07 M NaCl with the initial CIP concentration of 32.5 mg L −1 . The experimental efficiency was in satisfactory agreement with the predicted efficiency of 90.34%. The obtained results revealed that, sweep flocculation as a determinant mechanism controlled the adsorption of CIP molecules on aluminum hydroxide precipitates. Electrode consumption and electrical energy consumption were found to be 66.80 g m −3 and 0.613 kWh m −3 , respectively. The obtained results from real sample analysis revealed that the initial CIP concentration of 154 ± 6 μg L −1 of hospital wastewater were found to reached to zero after applying optimal condition of EC process.

Oxidation of ciprofloxacin and enrofloxacin by ferrate(VI): Products identification, and toxicity evaluation

Ferrate(VI) (Fe(VI)) has been known to react with emerging organic contaminants containing electron-rich organic moieties, such as phenols, anilines, olefins, reduced sulfur and deprotonated amines. Oxidation of fluoroquinolone antibiotics, ciprofloxacin (CIP) and enrofloxacin (ENR), by Fe(VI) were investigated for their reaction products and toxicity changes as well as biodegradability of these products. Ten products were identified for both CIP and ENR reactions with Fe(VI) using a high-resolution accurate-mass Orbitrap mass analyzer. Structural changes to the CIP and ENR molecule included dealkylation, formation of alcohols and amides in piperazine ring and oxygen transfer to the double bond in quinolone structure. An enamine formation mechanism was tentatively proposed to facilitate the interpretation of CIP and ENR oxidation pathways. Toxicity evaluation using Microbial Assay for toxicity Risk Assessment (MARA) bioassay indicated that Fe(VI) oxidation products of CIP and ENR contributed negligible antibacterial potency and Fe(VI) oxidation treatment can remove the residual toxicity of CIP and ENR impacted source waters. The Fe(VI) oxidation treatment resulted in formation of relatively more biodegradable products (based on in silico assessment) than their corresponding parent compounds. The results showed that Fe(VI) has a good potential to degrade fluoroquinolone antibiotics and their antimicrobial potency in natural waters.

Kinetics and Mechanisms of Ciprofloxacin Oxidation on Hematite Surfaces.

Adsorption of antibiotics at mineral surfaces has been extensively studied over the past 20 years, yet much remains to be learned on their interfacial properties and transformation mechanisms. In this study, interactions of Ciprofloxacin (CIP), a fluoroquinolone antibiotic with two sets of synthetic nanosized hematite particles, with relatively smooth (H10, 10-20 nm in diameter) and roughened (H80, 80-90 nm in diameter) surfaces, were studied by means of liquid chromatography (LC), mass spectrometry (MS), and spectroscopy (vibration and X-ray photoelectron). Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy provides evidence for inner-sphere bidentate complex formation of CIP at hematite surfaces in 0.01 M NaCl, irrespective of pH and particle size. ATR-FTIR spectroscopy also revealed that the sorbed mother CIP molecule decayed to other surface species over a period of at least 65 h. This was supported by the detection of three daughter products in the aqueous phase by LC/MS. The appearance of NH3(+) groups during the course of these experiments, revealed by cryogenic XPS, provides further evidence that CIP oxidation proceeds through an opening of piperazine ring via N-dealkylation. Additional in vacuo FTIR experiments under temperature-programmed desorption also showed that oxidation of sorbed byproducts were effectively degraded beyond 450 °C, a result denoting considerably strong (inter)molecular bonds of both mother and daughter products. This work also showed that rougher, possibly multidomainic particles (H80) generated slower rates of CIP decomposition but occurring through more complex schemes than at smoother particle surfaces (H10). This work thus uncovered key aspects of the binding of an important antibiotic at iron oxide surfaces, and therefore provided additional constraints to our growing understanding of the fate of emerging contaminants in the environment.

Degradation of ciprofloxacin and sulfamethoxazole by ferrous-activated persulfate: Implications for remediation of groundwater contaminated by antibiotics

The wide occurrence of antibiotics in groundwater raised great scientific interest as well as public awareness in recent years due to their potential ability to spread antibiotic resistant gene and pose risk to humans. The present study investigated the ferrous ion (Fe(II)) activated decomposition of persulfate (S2O82−), as a potential in situ chemical oxidation (ISCO) approach, for remediation of groundwater contaminated by antibiotics. Fe(II)-persulfate mediated ciprofloxacin (CIP) degradation was found to be more efficient than sulfamethoxazole (SMX) at near neutral pH (pH6.0), probably due to the higher electric density in CIP molecule and its ability to form complex with Fe(II) as a ligand. Hydroxyl (HO) and sulfate radical (SO4−) were determined to be responsible for the degradation of CIP and SMX in Fe(II)-persulfate system by molecular probes. No enhancement in the degradation of CIP was observed when citrate (CA), ethylenediaminetetraacetate (EDTA) and (S,S)-ethylenediamine-N,N′-disuccinate (EDDS) were used as Fe(II) chelating agents in Fe(II)-persulfate system. For SMX, CA and EDTA accelerated the degradation by Fe(II)-persulfate. Degradation of antibiotics in river water matrix was nearly the same as that in Milli-Q water, implying the possibility of using Fe(II)-persulfate for antibiotics depletion under environmentally relevant condition. A comparison of the degradation efficiency of SMX with other sulfonamides and sulfanilic acid indicated that the heterocyclic ring has a large impact on the degradation of sulfonamides. Transformation products of CIP and SMX by Fe(II)-persulfate were analyzed by solid phase extraction–liquid chromatography–mass spectrometry (SPE–LC–MS) technique. Based on the intermediate products, Fe(II)-persulfate mediated CIP degradation pathways were tentatively proposed.

Formulation and antibacterial profiles of clay–ciprofloxacin composites

The ability of clay minerals to adsorb and desorb drugs, including antibacterial molecules, is an attractive and exciting prospect for healthcare applications. The antibacterial ciprofloxacin was adsorbed onto kaolin, montmorillonite K-10, and Laponite® RD then the subsequent antibacterial activity of the composites formed was confirmed. The effects of time, pH, and CIP concentration were investigated. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were used to confirm the mechanism of ciprofloxacin adsorption onto the clay minerals. Dispersion pH was the most important variable influencing the adsorption of ciprofloxacin onto the clay minerals and the mechanism of adsorption was confirmed as cation exchange. Adsorption isotherms and application of Langmuir and Freundlich models showed that a ciprofloxacin monolayer was formed at different concentrations on each of the clay minerals tested. Kinetic studies showed that maximal CIP adsorption was achieved within the first hour of adsorption. Antibacterial activity of clay–ciprofloxacin composites against the common skin bacteria Staphylococcus epidermidis and Propionibacterium acnes was demonstrated. This work showed that clay–ciprofloxacin composites are potential delivery systems for ciprofloxacin molecules. As a result, this could make them ideal candidates to take forward for healthcare applications, including the development of novel wound dressings.

Removal of ciprofloxacin from water by birnessite

With more pharmaceuticals and personal care products detected in the surface and waste waters, studies on interactions between these contaminants and soils or sediments have attracted great attention. In this study, the removal of ciprofloxacin (CIP), a fluoroquinolone antibiotic, by birnessite, a layered manganese oxide, in aqueous solution was investigated by batch studies supplemented by X-ray diffraction (XRD) and Fourier transform infrared analyses. Stoichiometric release of exchangeable cations accompanying CIP removal from water confirmed cation exchange as the major mechanism for CIP uptake by birnessite. Interlayer expansion after CIP adsorption on birnessite as revealed by XRD analyses indicated that intercalation contributed significantly to CIP uptake in addition to external surface adsorption. Correlation of CIP adsorption to specific surface area and cation exchange capacity suggested that the former was the limiting factor for CIP uptake. At the adsorption maximum, CIP molecules formed a monolayer on the birnessite surfaces. The adsorbed CIP could be partially removed using a cationic surfactant at a low initial concentration and mostly removed by AlCl3 at a higher initial concentration, which further supported the cation exchange mechanism for CIP removal by birnessite. The results indicated that the presence of layered Mn-oxide in the soil and waste water treatment systems may provide host for CIP accumulation.

Adsorption of ciprofloxacin and its role for stabilizing multi-walled carbon nanotubes and characterization

In this study, multi-walled carbon nanotubes (MWCNTs) were dispersed in an aqueous solution using ciprofloxacin (CF) without chemical modification. We found that CF is a useful stabilizer for MWCNTs and the dispersions were stable for more than one month. Scanning electron microscopy, Uv–visible spectroscopy and cyclic voltammetry (CV) showed MWCNTs coated with CF molecules. Dry film of MWCNTs/CF was prepared and characterized by SEM, Uv–vis and CV. MWCNTs/CF dry film can be used as a biocompatible platform for other applications including protein and enzyme immobilization.

PH-dependent ciprofloxacin sorption to soils: Interaction mechanisms and soil factors influencing sorption

A study of ciprofloxacin sorption to 30 soils from the eastern United States revealed a statistically significant effect of pH on the solid–water distribution coefficient ( K d). Cation exchange capacity was the key soil factor influencing the extent of sorption at all pH values (3–8), with soil metal oxide content playing a smaller role at higher pH. Although, cation exchange, cation bridging and surface complexation mechanisms all appeared to contribute to the net extent of ciprofloxacin sorption to soils, the ciprofloxacin molecule appeared to be best suited for cation exchange. Notably, the ciprofloxacin cation (dominant at pH ≤ 5) exhibited a greater potential for cation exchange than the net neutral zwitterion (relevant at pH > 6). In addition to ciprofloxacin speciation in aqueous solution, the availability of surface sites for cation exchange (cation exchange capacity) and surface complexation (metal oxide content) played a key role in determining the shape of the pH edge and the potential contributions from individual sorption mechanisms to the net extent of sorption. Soils not limited by the availability of cation exchange sites and possessing a high effective cation exchange capacity (ECEC > 20 cmol c/kg), exhibited distinct pH edges (general decrease in sorption with pH) and the highest extent of sorption at all pH values. In these soils, cation exchange was found to be a dominant mechanism of sorption, with potential contributions from cation bridging and surface complexation being either unimportant or not discernable. In soils of lower cation exchange capacity (ECEC < 20 cmol c/kg), limited with respect to the availability of cation exchange sites, sorption initially increased with increasing pH, peaked at pH 5.5 and decreased at pH 7–8. In these soils, a specific contribution from surface complexation to the net extent of sorption was surmised at high pH values in metal oxide-rich soils, possessing low cation exchange capacities.

Ciprofloxacin@SiO2: Fluorescent nanobubbles

We report a new nanomaterial in which ciprofloxacin molecules are incorporated inside silica nanobubbles, denoted as ciprofloxacin@SiO2. The material has been characterised using UV/Vis absorption spectroscopy, transmission electron microscopy, cyclic voltammetry, and emission spectroscopy. The material is stable and the freestanding particles can be precipitated and redispersed in several solvents. Confinement of the molecule is complete as leaching through the shell is minimal. The material behaves like free ciprofloxacin in solution; however, effects of confinement are manifested. Energy transfer reaction between ciprofloxacin@SiO2 and Tb3+ was monitored by emission spectroscopy. The emission intensity decreased with metal ion exposure indicating selective electronic interaction.

Biological characterization of a novel biodegradable antimicrobial polymer synthesized with fluoroquinolones.

Biomaterial-related infections continue to represent a significant challenge to the medical community. Several approaches have been utilized to incorporate antimicrobial agents at the surface of implant devices in attempts to delay or eliminate the formation of biofilms. To date, most of these strategies have focused on drug conjugation or diffusion-limited systems for the delivery of such pharmaceutical agents. More recently, work has been presented on the feasibility of incorporating drugs into the backbone of polymers as a main-chain monomer. When sequenced into the backbone of the polymer with other monomers that are hydrolytically sensitive to enzyme-catalyzed breakdown, it is thought that drugs may be able to be selectively released. Specifically, degradable polyurethanes have been synthesized with fluoroquinolone antibiotics and have shown an ability to kill bacteria when released following degradation of the polymer chains by the macrophage-derived enzyme cholesterol esterase. However, specificity of the cleavage sites in the polymer was difficult to control. Since cholesterol esterase has specificity for hydrophobic moieties, it is desirable to alter the formulation of the polyurethanes to incorporate long hydrophobic monomers immediately adjacent to the ciprofloxacin molecule. Hence, the current study focuses on evaluating the enzyme-catalyzed degradation of a degradable polyurethane synthesized with 1,12 diisocyanatododecane as a substitute for 1,6 diisocyanatohexane, which was used in previous work. Validation of specific ciprofloxacin release and the generation of antimicrobial are shown. A preliminary cell study to assess the cytotoxicity of this biodegradable antibiotic polymer shows that the material has no observable effects on cell proliferation or cell membrane structure.

The Thermal Stability of Ciprofloxacin Complexes with Magnesium(II), Zinc(II) and Cobalt(II)

The thermal behaviour of Mg(II), Zn(II) and Co(II) compounds of ciprofloxacin was studied by thermogravimetry (TG) and differential thermal analysis (DTA) in order to determine or to confirm some structural characteristics of substances. The complexes decompose in two steps: dehydration and pyrolytic decomposition of the anhydrous complexes to form metal oxide or metal fluoride. The dehydration process of one magnesium(II) compound takes place in two steps suggesting a marked difference in the bonding of water molecules. The different bonding mode of the ciprofloxacin molecules in both magnesium compounds leads to different residues of the thermal decompositions.