Mutagenicity of quinolone antibacterials.

The literature is summarised on the activity of quinolone antibacterial compounds in assays which are commonly used for risk assessment of new pharmaceuticals. These include assays for DNA damage, sister chromatid exchanges, chromosome aberrations and mutation induction. The general pattern of activity exhibited by these compounds is induction of DNA damage in both prokaryotic and eukaryotic cells, and induction of mutations in DNA repair-proficient bacteria and at the thymidine kinase locus in mammalian cells. They do not appear as a class to induce mutations at the hypoxanthine-guanine-phosphoribosyltransferase (HGPRT) or Na+,K(+)-ATPase loci or to cause chromosome aberrations. It is suggested that these actions may be the result of interference with eukaryotic topoisomerase and that this interference differs in some respects from the topoisomerase interference caused by certain antitumour compounds. The postulated mechanism of action has important implications for assessment of risk from consumption of quinolone antibacterials. The risk of adverse genotoxic events should vary directly with the concentration of drug reaching the intracellular enzyme target and the affinity of the drug for the target. Results of carcinogenicity studies conducted to date with the quinolone antibacterials suggest minimal risk from long term consumption of the newer, second-generation compounds.     

Drug interactions with quinolone antibacterials.

The quinolone antibacterials are prone to many interactions with other drugs. Quinolone absorption is markedly reduced with antacids containing aluminium, magnesium and/or calcium and therapeutic failure may result. Other metallic ion-containing drugs, such as sucralfate, iron salts, and zinc salts, can also reduce absorption. Some of the newer quinolones inhibit the cytochrome P450 system, e.g. enoxacin, pefloxacin and ciprofloxacin. The toxicity of drugs that are metabolised by the cytochrome P450 system is enhanced by concomitant use of some quinolones. Ciprofloxacin, enoxacin and pefloxacin can increase theophylline concentrations to toxic values. The pharmacokinetics of warfarin and cyclosporin are unaffected. Ofloxacin, fleroxacin and temafloxacin have a low inhibitory effect on the cytochrome P450 system and a low interaction potential may result. The affinity of quinolones for the gamma-aminobutyric acid (GABA) receptor may induce CNS adverse effects; these effects are enhanced by some nonsteroidal anti-inflammatory drugs (NSAIDs).     

1-取代苄基喹啉酮酸衍生物的合成与抗菌活性

喹啉酮酸类化合物是近年来研究发展十分迅速的广谱、高效、低毒的抗菌药物。作者合成并测定了近三十个6-氟-7-取代氨基取代的1-取代苄基喹啉酮酸类化合物,对金黄色葡萄球菌25923,大肠杆菌25922以及绿脓杆菌的MIC(μg/ml)值。结果表明,这类化合物的体外抗菌活性均较低,对革兰氏阳性菌的作用相对强于对革兰氏阴性菌的作用。1-取代苄基抗菌活性顺序一般为:苄基>对氯苄基>对硝基苄基。     

Synthesis and antibacterial evaluation of certain quinolone derivatives.

A number of 7-substituted quinolone derivatives were synthesized and evaluated for antibacterial and cytotoxic activities. Preliminary results indicated that most compounds tested in this study demonstrated better activity against methicillin-resistant Staphylococcus aureus than norfloxacin. Among them, 1-(4-amino-2-fluorophenyl)-6-fluoro-1,4-dihydro-7-[4-[2-(4-methoxyphenyl)-2-hydroxyiminoethyl]-1-piperazinyl]-4-oxo-3-quinolinecarboxylic acid (11d) and its ketone precursor 10d exhibited significant activities against Klebsiella pneumoniae, methicillin-resistant S. aureus, erythromycin- and ampicillin-resistant Streptococcus pneumoniae, and vancomycin-resistant Enterococcus faecalis. Due to strong cytotoxicities of 11d (a mean log GI(50) of -5.40), compound 10d, with good antibacterial activities and low cytotoxicities (a mean log GI(50) of -4.67), is a more potential drug candidate.     

Protonation equilibria of quinolone antibacterials

The acid-base properties of seven antibacterial 7-piperazinyl fluoroquinolone derivatives were studied by potentiometry and UV and NMR spectroscopy. These molecules contain two proton-binding sites of similar basicity, namely, the piperazine amino and the carboxylate groups, as proven by 1H NMR spectroscopy. The basicities are quantitated at the molecular level in terms of macroconstants, and also at the submolecular level in terms of microconstants. The microconstants are then used to calculate the concentration of the positive, zwitterionic, neutral, and negatively charged species (microspeciation). The zwitterionic forms always predominate over their neutral protonation isomers, but the zwitterionic:neutral concentration ratio is considerably different for the examined fluoroquinolone derivatives.     

Synthesis and biological activity of benzothiazolo[3,2-a]quinolone antibacterial agents

A new class of heterocyclic compounds with potent antibacterial activity, namely, 2-substituted amino-3-fluoro-5,12-dihydro-5-oxobenzothiazolo[3, 2-a]quinoline-6-carboxylic acids, is described. The compounds are conformationally restricted analogues of 7-substituted amino-6-fluoro-1-aryl-1, 4-dihydro-4-oxoquinoline-3-carboxylic acids. Compounds 7 and 10, having a 4-methylpiperazinyl and a piperazinyl substitution at the 2-position, respectively, possess in vitro antibacterial activities comparable to norfloxacin (15). Compound 8, which has a 4-acetylpiperazinyl substitution at the 2-position, is active against Gram-positive organisms and nearly inactive against Gram-negative organisms. An efficient and short synthesis of this novel heterocyclic system via an intramolecular nucleophilic displacement cyclization reaction is reported.     

喹诺酮类抗菌药的研究进展

综述了近年喹诺酮类抗菌药的抗菌活性和临床应用进展，包括近年上市的第四代喹诺酮类抗菌药莫西沙星、加替沙星、吉米沙星和巴洛沙星，与结构经进一步深入修饰的喹诺酮类抗菌药如帕珠沙星和鲁利沙星，还概述了正在研发中的新药。     

Synthesis and antibacterial activity of new poly-S-lysine-porphyrin conjugates

Studies on the synthesis, structural elucidation, and biological evaluation of new conjugates of poly-S-lysine with meso-substituted porphyrins are described. The new conjugates were used in the photoinactivation of antibiotic-resistant Gram-positive bacteria (Staphylococcus aureus strains ATCC 25923 and MRSA 110) and Gram-negative bacteria (Escherichia coli strain O4). The results show that the cationic conjugates are able to photosensitize the efficient inactivation of both types of bacteria.     

Synthesis and antibacterial activity of some new hydrazones

New hydrazone derivatives were synthesized by the condensation of some selected heteroaromatic hydrazines with appropriate aromatic ketones at high temperature (100 °C). The structures of the synthesized compounds were established by elemental (CHN) and spectral (IR, ¹HNMR, and Mass) analysis. The synthesized compounds were screened for their antibacterial (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Proteus mirabilis) activities, which reveal that all the compounds possess activity against all the tested organisms.     

新型喹啉酸咪唑乙酯类化合物的合成及活性研究

目的：设计合成新型的抗厌氧菌喹诺酮类药物。方法：首先由1-羟乙基-2-甲基-5-硝基咪唑经氯代、碘交换生成1-碘乙基-2-甲基-5-硝基咪唑，然后再与各种哌嗪4位取代的1-烷基-6-氟-7-哌嗪基-1，4-二氢-4-氧代喹啉-3-羧酸作用生成目标化合物。结果：设计合成了一系列新型含咪唑结构的喹啉酸乙酯类似物，利用元素分析、核磁共振进行了结构确认，活性测试表明所合成的16个化合物中，化合物d4、d15的抗厌氧菌活性略高于甲硝唑，体外抗革兰氏阴性细菌的活性低于对照物诺氟沙星。     

Synthesis and antitumor activity of fused tetracyclic quinoline derivatives. 1

Several fused tri- and tetracyclic quinolines (I and II) with [2-methoxy-4-[(methylsulfonyl)amino]phenyl]amino or [3-(N,N-dimethylamino)propyl]amino side chains were prepared, and their DNA intercalative properties, KB cytotoxicity, antitumor activity (P388 leukemia), and ability to induce topoisomerase II dependent DNA cleavage were investigated. Some compounds having both intercalative ability and KB cytotoxicity were found to be inactive in vivo. However, a positive correlation was seen between the ability to induce topoisomerase II dependent DNA cleavage and antitumor activity in vivo. The indeno- (13a), benzofuro- (21a), and benzothieno- (22a) quinoline derivatives exhibited potent antitumor activities in vitro and in vivo, comparable to those of m-AMSA. They also intercalate DNA and induce topoisomerase II dependent DNA cleavage. Extended screening of 13a showed it to be active against solid tumors such as M5076 sarcoma, B16 melanoma, and colon 38 carcinoma.     

Delafloxacin:一种新型喹诺酮类抗菌药物

2017年6月19日FDA首次批准Delafloxacin(DLX)上市,为临床医师治疗耐甲氧西林金黄色葡萄球菌(MRSA)及其他病原菌引起的急性细菌性皮肤和皮肤结构感染提供了一种新的选择。DLX是一种喹诺酮类广谱抗菌药物,临床研究显示,其在酸性环境中的抗菌效果更佳,无QT间期延长和光毒性,也没有显示对肝功能、肾功能和葡萄糖利用的不良影响。除与螯合剂外,几乎不与其他药物发生不良相互作用。本文就DLX的作用机制和抗菌活性、药动学、药效学、安全性和耐受性及在抗菌治疗中的前景进行综述。     

莫西沙星8-二氟甲氧基类似物的合成与体内外抗菌作用

1-环丙基-6，7-二氟-8-甲氧基-1，4-二氢．4-氧代喹啉．3-羧酸乙酯依次经醚键断裂、酯化、二氟甲基醚化得1．环丙基-6，7-二氟-8-二氟甲氧基-1，4-二氢-4-氧代喹啉．3-羧酸乙酯，然后经过螫合、与[1S，6S]-2．叔丁氧羰基．2，8．二氮杂双环[4，3，0]壬烷缩合、最后脱除叔丁氧羰基保护得到1-环丙基．8．二氟甲氧基-7-[（1S，6S）．2，8．二氮杂双环[4，3，0]壬烷．8．基]-6-氟．1，4-二氢-4-氧代喹啉-3-羧酸。目标化合物的结构经核磁共振氢谱和质谱（ESI）所确证，并测定了其体内外抗菌作用，结果表明该化合物优于对照药环丙沙星，与莫西沙星相当或略优，尤其对肺炎链球菌29074的体内活性突出，值得深入评价。     

Synthesis and antibacterial activity of new cephalosporins with lactonyloxyimino moiety

A series of 7-{2-(2-aminothiazol-4-yl)-2-Z-(γ-lacton-3-yl) oxyiminoacetamidol} cephalosporins with various substituents at the 3-position in cephem nucleus were synthesized and evaluated microbiologically. The tested compounds showed potent activities but were somewhat less active than cefotaxime or cefixime against a wide variety of Gram-positive and Gram-negative bacteria.