Synthesis, crystal structure, and characterization of two metal-quinolone compounds

Turel, Iztok; Leban, I.; Klintschar, Gerd; Bukovec, N.; Zalar, Stane

doi:10.1016/s0162-0134(96)00157-2

Cited by 83 publications

(61 citation statements)

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“…In previous studies, metal complexes of quinolones isolated from acidic media usually contain singly and/or doubly protonated quinolones that are incapable of bonding to the metal ion and in these cases only electrostatic interaction was observed between the drug and the metal ions. 15,16 Here in we also propose that ionic interaction existed between the drug and metal ion in acidic medium. At low pH, the ring carbonyl oxygen of enoxacin is protonated 17 or the hydrogen atom of the carboxylic group is hydrogen bonded to the carbonyl oxygen atom, 18 giving it a partial positive charge.…”

Section: Spectrophotometric Analysismentioning

confidence: 67%

“…Hence, it is proposed that chemical species formed in acidic media are ionic in nature, consisting of protonated enoxacin cation and chlorometalate anion. 15 Their UV spectra in comparison with the drug alone indicates a red shift of absorption band at 268-262 nm which is due to charge stabilization of intra-ligand C 6 =C 7 π→π * transitions upon interaction with the metal ions. 19 The proposed mechanism of interaction between enoxacin and metal cations in neutral and basic medium is chelation between the metal and the 4-oxo and adjacent 3-carboxyl groups.…”

Section: Spectrophotometric Analysismentioning

confidence: 98%

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Effect of metal ions on the in vitro availability of enoxacin, its in vivo implications, kinetic and antibacterial studies

et al. 2011

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Recebido em 10/10/09; aceito em 17/8/10; publicado na web em 7/1/11The present paper describes the effect of metals ions on the in vitro availability of enoxacin (a second generation quinolone antibiotic) owing to drug-metal interaction. These interaction studies were performed at 37 °C in different pH environments simulating human body compartments and were studied by UV spectroscopic technique. In order to determine the probability of these reactions different kinetic parameters (dissolution constants (K) and free energy change (∆G)) for these reactions were also calculated. It is proposed that the structure of enoxacin contains various electron donating sites which facilitate its binding with metallic cations forming chelates. Hence taking food products, nutritional supplements or multivitamins containing multivalent cations at the same time as enoxacin, could reduce the absorption of the drug into the circulation and thus would decrease the effectiveness of the drug. In addition, the MIC of enoxacin for various microorganisms before and after interaction with metal ions was calculated which in most cases was increased which possibly could impair the clinical efficacy of the drug.

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Section: Spectrophotometric Analysismentioning

confidence: 67%

Section: Spectrophotometric Analysismentioning

confidence: 98%

Effect of metal ions on the in vitro availability of enoxacin, its in vivo implications, kinetic and antibacterial studies

et al. 2011

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“…[67][68][69][70][71][72][73] O efeito do íon metálico na atividade antibacteriana da norfloxacina pode ser ilustrado pelo trabalho de Gao e colaboradores, 73 que mostraram que os complexos de Fe(III) e Zn(II) apresentam atividade superior à da norfloxacina contra E. coli e B. dysenteriae.…”

Section: Coordenação De Metais a Quinolonas E Fluorquinolonasunclassified

“…A literatura reporta complexos com ciprofloxacina, [74][75][76][77][78] esparfloxacina, 79 cinoxacina, [80][81][82] ácido nalidíxico 83 e norfloxacina. [84][85][86] Complexos de cobre contendo a esparfloxacina e ligantes nitrogenados foram recentemente relatados 87 e estão entre os mais ativos contra Escherichia coli, Pseudomonas aeruginosa e Staphylococcus aureus, quando comparados com outros complexos de cobre contendo …”

Section: Coordenação De Metais a Quinolonas E Fluorquinolonasunclassified

Coordenação de metais a antibióticos como uma estratégia de combate à resistência bacteriana

Rocha¹,

Pinto²,

Ruggiero³

et al. 2011

Quím. Nova

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Recebido em 12/1/10; aceito em 2/8/10; publicado na web em 16/11/10 COORDINATION OF METALS TO ANTIBIOTICS AS A STRATEGY TO COMBAT BACTERIAL RESISTANCE. Antibiotic resistance has been growing at an alarming rate and consequently the arsenal of effective antibiotics against Gram-negative and Gram-positive bacteria has dropped dramatically. In this sense there is a strong need to produce new substances that not only have good spectrum of activity, but having new mechanisms of action. In this regard, this paper emphasizes the coordination of metals to antibiotics as a strategy for reversing antibiotic resistance and production of new drugs, with a special focus on quinolones, fluoroquinolones, sulfonamides and tetracyclines.Keywords: antibiotics; metal-based drugs; bacterial resistance. INTRODUÇÃOA descoberta dos antibióticos representa um dos mais importantes marcos da medicina moderna. A introdução das sulfonamidas em 1930 e da penicilina na década posterior provocaram um grande avanço no tratamento de doenças infecciosas, causando uma drásti-ca diminuição nas taxas de mortalidade e uma enorme sensação de bem-estar. 1 O sucesso dos primeiros antibióticos na cura de doenças até então consideradas letais acarretou uma intensa busca por novas drogas. De fato, as décadas de 40, 50 e 60 do século passado foram marcadas pela imensa quantidade de antibióticos produzidos e rapidamente incorporados às práticas clínicas. 2 No entanto, nas décadas posteriores houve um declínio na produção destes compostos. Entre o lançamento das quinolonas em 1962 até a aprovação das oxazolidinonas em 2000, houve pouca inovação no que se refere à introdução de novas classes de antibióticos de uso clínico bem-sucedido. 2 Quando um antibiótico é descoberto e introduzido no mercado, sua utilidade clínica começa a diminuir até um ponto em que há um aumento na restrição de seu uso. Esta restrição é provocada pelo surgimento de cepas resistentes. As bactérias surgiram na terra há bilhões de anos e para sobreviver desenvolveram mecanismos de resistência aos antibióticos que são encontrados livres na natureza. 3 Portanto, não é surpreendente o fato de que muitos antibióticos lançados nas últimas décadas, que são em sua ampla maioria de origem natural ou semissintética, terem utilidade limitada na época de sua descoberta e em pouco tempo se tornarem obsoletos. 3 Outro fator que contribui muito para tornar um antibiótico menos eficiente é a sua utilização indiscriminada e incorreta, o que vem a favorecer o surgimento de micro-organismos resistentes. Atualmente, algumas classes de micro-organismos representam extrema preocupação para a saúde publica. Dentre os que mais provocam mortes no mundo estão o Staphylococcus aureus meticilina-resistente (MRSA), Staphylococcus aureus vancomicina-resistente (VRSA), Escherichia coli, Klebsiella pneumoniae e Pseudomonas aeruginosa, que são bactérias resistentes a múltiplas drogas. Os processos infecciosos causados por estas classes de micro-organismos geralmente estão associados com alta letalidade e altos custos d...

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“…hydrochloride, lactate, methanesulfonate) and it was additionally found that for norfloxacin even the double hydrochloride salt could be prepared from highly acidic media. 2 The title compound was isolated in our unsuccessful attempts to prepare a magnesium complex of cf from aqueous solutions. The crystals of the product formed after slow isothermal evaporation of the mother liquor solution.…”

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confidence: 99%

Crystal Structure of Ciprofloxacin Hydrochloride 1.34-Hydrate

Turel

Golobič

2003

ANAL. SCI.

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Ciprofloxacin (1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinoline carboxylic acid = cf) is a member of the family of quinolone antibacterial agents (Fig. 1). Several quinolones are used in clinical practice for treatment of various bacterial infections.Most quinolones are only sparingly soluble in the pH range from 4 to 9 due to the formation of zwitterions, which are in some cases present also in a solid state, as in the example of ciprofloxacin hexahydrate. 1 The solubility of the quinolones is increased in the form of simple salts (e.g. hydrochloride, lactate, methanesulfonate) and it was additionally found that for norfloxacin even the double hydrochloride salt could be prepared from highly acidic media. 2 The title compound was isolated in our unsuccessful attempts to prepare a magnesium complex of cf from aqueous solutions. The crystals of the product formed after slow isothermal evaporation of the mother liquor solution.The crystal and experimental data are given in Table 1. The structure was solved by the direct methods. The positions of hydrogen atoms were obtained from the difference Fourier map. We employed full-matrix least-squares refinement on F magnitudes with anisotropic displacement factors for nonhydrogen atoms and isotropic ones for hydrogen atoms. Ciprofloxacin belongs to a family of quinolone antibacterial agents. The crystal structure of ciprofloxacin hydrochloride 1.34-hydrate was determined. Most of the bond lengths and angles of the ciprofloxacin cation are very similar to those of ciprofloxacin hexahydrate, which appears in the zwitterionic form. The exceptions are the carbon-oxygen bond distances in the carboxylic group, since in the title compound this group is not deprotonated. Various inter-and intramolecular hydrogen bonds were found in the molecule and are described. Table 1 Crystal and experimental data *Included were those "less than" refl. for which Fc was greater than Fo. Fig. 2 The view of the asymmetric unit of the title compound with labeling of nonhydrogen atoms (ellipsoids are at 50% probability level).

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Synthesis, crystal structure, and characterization of two metal-quinolone compounds

Cited by 83 publications

References 10 publications

Effect of metal ions on the in vitro availability of enoxacin, its in vivo implications, kinetic and antibacterial studies

Effect of metal ions on the in vitro availability of enoxacin, its in vivo implications, kinetic and antibacterial studies

Coordenação de metais a antibióticos como uma estratégia de combate à resistência bacteriana

Crystal Structure of Ciprofloxacin Hydrochloride 1.34-Hydrate

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