Distinct photolytic mechanisms and products for different dissociation species of ciprofloxacin.

As many antibiotics are ionizable and may have different dissociation forms in the aquatic environment, we hypothesized that the different dissociation species have disparate photolytic pathways, products, and kinetics, and adopted ciprofloxacin (CIP) as a case to test this hypothesis. Simulated sunlight experiments and matrix calculations were performed to differentiate the photolytic reactivity for each dissociation species (H4CIP(3+), H3CIP(2+), H2CIP(+), HCIP(0), and CIP(-)). The results prove that the five dissociation species do have dissimilar photolytic kinetics and products. H4CIP(3+) mainly undergoes stepwise cleavage of the piperazine ring, while H2CIP(+) mainly undergoes defluorination. For H3CIP(2+), HCIP(0), and CIP(-), the major photolytic pathway is oxidation. By density functional theory calculation, we clarified the defluorination mechanisms for the five dissociation species at the excited triplet states: All the five species can defluorinate by reaction with hydroxide ions (OH(-)) to form hydroxylated products, and H2CIP(+) can also undergo C-F bond cleavage to produce F(-) and a carbon-centered radical. This study is a first attempt to differentiate the photolytic products and mechanisms for different dissociation species of ionizable compounds. The results imply that for accurate ecological risk assessment of ionizable emerging pollutants, it is necessary to investigate the environmental photochemical behavior of all dissociation species.

[1]  Lee E. Brown,et al.  Global Synthesis and Critical Evaluation of Pharmaceutical Data Sets Collected from River Systems , 2012, Environmental science & technology.

[2]  M. Sturini,et al.  Photodegradation of fluoroquinolones in surface water and antimicrobial activity of the photoproducts. , 2012, Water research.

[3]  Kyungho Choi,et al.  Pharmaceuticals and Personal Care Products in the Environment: What Are the Big Questions? , 2012, Environmental health perspectives.

[4]  M. Sturini,et al.  Photolytic and photocatalytic degradation of fluoroquinolones in untreated river water under natural sunlight , 2012 .

[5]  Yong Wang,et al.  Computational toxicological investigation on the mechanism and pathways of xenobiotics metabolized by cytochrome P450: a case of BDE-47. , 2012, Environmental science & technology.

[6]  A. Ruban,et al.  A theoretical investigation of xanthophyll-protein hydrogen bonding in the photosystem II antenna. , 2012, The journal of physical chemistry. B.

[7]  S. Trapp,et al.  Optimal choice of pH for toxicity and bioaccumulation studies of ionizing organic chemicals , 2011, Environmental toxicology and chemistry.

[8]  Linus Sandegren,et al.  Selection of Resistant Bacteria at Very Low Antibiotic Concentrations , 2011, PLoS pathogens.

[9]  Xianliang Qiao,et al.  Quantum chemical investigation on the mechanism and kinetics of PBDE photooxidation by ·OH: a case study for BDE-15. , 2011, Environmental science & technology.

[10]  Jingwen Chen,et al.  Quantum chemical investigation and experimental verification on the aquatic photochemistry of the sunscreen 2-phenylbenzimidazole-5-sulfonic acid. , 2010, Environmental science & technology.

[11]  C. Woodward.  Animal antibiotics under tougher United States scrutiny as consensus grows on “superbug” risk to humans , 2010, Canadian Medical Association Journal.

[12]  D. Mackay,et al.  Activity-based concept for transport and partitioning of ionizing organics. , 2010, Environmental science & technology.

[13]  E. Fasani,et al.  Photochemical degradation of marbofloxacin and enrofloxacin in natural waters. , 2010, Environmental science & technology.

[14]  T. Strathmann,et al.  Photolytic and photocatalytic decomposition of aqueous ciprofloxacin: transformation products and residual antibacterial activity. , 2010, Water research.

[15]  H. Mamane,et al.  pH induced polychromatic UV treatment for the removal of a mixture of SMX, OTC and CIP from water. , 2010, Journal of hazardous materials.

[16]  Xiaoxuan Wei,et al.  Aquatic photochemistry of fluoroquinolone antibiotics: kinetics, pathways, and multivariate effects of main water constituents. , 2010, Environmental science & technology.

[17]  S. Trapp,et al.  An unexpected challenge: ionizable compounds in the REACH chemical space , 2010 .

[18]  J. Dewulf,et al.  Levofloxacin ozonation in water: rate determining process parameters and reaction pathway elucidation. , 2009, Chemosphere.

[19]  Jingwen Chen,et al.  Light-source-dependent effects of main water constituents on photodegradation of phenicol antibiotics: mechanism and kinetics. , 2009, Environmental science & technology.

[20]  C. Gagnon,et al.  Review of the Occurrence of Anti-infectives in Contaminated Wastewaters and Natural and Drinking Waters , 2009, Environmental health perspectives.

[21]  A. Sapkota,et al.  Aquaculture practices and potential human health risks: current knowledge and future priorities. , 2008, Environment international.

[22]  D. Truhlar,et al.  The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other functionals , 2008 .

[23]  Gerald T Ankley,et al.  Repeating history: pharmaceuticals in the environment. , 2007, Environmental science & technology.

[24]  D. Larsson,et al.  Effluent from drug manufactures contains extremely high levels of pharmaceuticals. , 2007, Journal of hazardous materials.

[25]  Jianying Hu,et al.  Quantitative Structure−Activity Relationship Model for Prediction of Genotoxic Potential for Quinolone Antibacterials , 2007 .

[26]  R. Schwarzenbach,et al.  The Challenge of Micropollutants in Aquatic Systems , 2006, Science.

[27]  T. Ohno,et al.  Theoretical studies of phosphorescence spectra of tris(2,2'-bipyridine) transition metal compounds. , 2006, Inorganic chemistry.

[28]  W. Arnold,et al.  Water hardness as a photochemical parameter: tetracycline photolysis as a function of calcium concentration, magnesium concentration, and pH. , 2006, Environmental science & technology.

[29]  J. Tomasi,et al.  Quantum mechanical continuum solvation models. , 2005, Chemical reviews.

[30]  W. Arnold,et al.  Triplet-sensitized photodegradation of sulfa drugs containing six-membered heterocyclic groups: identification of an SO2 extrusion photoproduct. , 2005, Environmental science & technology.

[31]  C. Knapp,et al.  Factors Affecting the Fate of Ciprofloxacin in Aquatic Field Systems , 2005 .

[32]  C. Adams,et al.  Potentiometric determination of acid dissociation constants (pKa) for human and veterinary antibiotics. , 2004, Water research.

[33]  W. Arnold,et al.  Photochemical fate of sulfa drugs in the aquatic environment: sulfa drugs containing five-membered heterocyclic groups. , 2004, Environmental science & technology.

[34]  S. Monti,et al.  Photophysics and photochemistry of fluoroquinolones. , 2003, Chemical Society reviews.

[35]  E. Fasani,et al.  Photochemistry of 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7- (piperazin-1-yl)quinoline-3-carboxylic acid (=ciprofloxacin) in aqueous solutions , 2001 .

[36]  F. Abildgaard,et al.  NMR of hydrogen bonding in cold‐shock protein A and an analysis of the influence of crystallographic resolution on comparisons of hydrogen bond lengths , 2001, Protein science : a publication of the Protein Society.

[37]  S. Sortino,et al.  Multifaceted photoreactivity of 6-fluoro-7-aminoquinolones from the lowest excited states in aqueous media: a study by nanosecond and picosecond spectroscopic techniques. , 2001, Chemistry.

[38]  G. Condorelli,et al.  Molecular Mechanism of Photosensitization XI. Membrane Damage and DNA Cleavage Photoinduced by Enoxacin , 1998, Photochemistry and photobiology.

[39]  A. Markham,et al.  Ciprofloxacin. An updated review of its pharmacology, therapeutic efficacy and tolerability. , 1996, Drugs.

[40]  K. Torniainen,et al.  The effect of pH, buffer type and drug concentration on the photodegradation of ciprofloxacin , 1996 .

[41]  A. Becke.  Density-functional thermochemistry. III. The role of exact exchange , 1993 .

[42]  A. Becke,et al.  Density-functional exchange-energy approximation with correct asymptotic behavior. , 1988, Physical review. A, General physics.

[43]  T. Mill,et al.  Development and evaluation of sunlight actinometers. , 1982, Environmental science & technology.

[44]  K. Fukui.  The path of chemical reactions - the IRC approach , 1981 .

[45]  Klaus Kümmerer,et al.  Biodegradability of 14C-labeled antibiotics in a modified laboratory scale sewage treatment plant at environmentally relevant concentrations. , 2006, Environmental science & technology.

[46]  K. Gollnick,et al.  Photosensibilisierte oxygenierung von aminen. Mechanismus der reaktion von singulett-sauerstoff mit aminen. , 1973 .