Search results for "Quinolones"

Use of HepG2 cell line for direct or indirect mutagens screening: comparative investigation between comet and micronucleus assays.

2003

International audience; In the present study, DNA-damage and clastogenic or aneugenic effects of genotoxic compounds were examined in a metabolically competent human cell line (HepG2 cells) using the micronucleus and the comet assays. Compounds with various action mechanisms were tested: direct mutagens such as 4-nitroquinoline-N-oxide (4-NQO) and methyl methanesulfonate (MMS) and indirect mutagens requiring biotransformation to be active such as N-nitrosodimethylamine (NDMA), benzo[a]pyrene (B[a]P) and 2-acetylaminofluorene (2-AAF). The compounds were first tested for cytotoxicity by measuring their effects on RNA synthesis inhibition in HepG2 cells. 4-NQO, B[a]P and 2-AAF were the most po…

Kinetic modelling of passive transport and active efflux of a fluoroquinolone across Caco-2 cells using a compartmental approach in NONMEM.

2005

The purpose was to develop a general mathematical model for estimating passive permeability and efflux transport parameters from in vitro cell culture experiments. The procedure is applicable for linear and non-linear transport of drug with time,10 or10% of drug transport, negligible or relevant back flow, and would allow the adequate correction in the case of relevant mass balance problems. A compartmental kinetic approach was used and the transport barriers were described quantitatively in terms of apical and basolateral clearances. The method can be applied when sink conditions are not achieved and it allows the evaluation of the location of the transporter and its binding site. In this …

Domino Synthesis of 3-Alkyliden-2,3-Dihydro-4-Quinolones

2019

Activity–Bioavailability balance in Oral Drug Development for a Selected Group of 6‐Fluoroquinolones

2002

Abstract A nomogram is proposed to select the best candidate in drug development studies with quinolones and is intended to substitute other possible models. The nomogram is referred to as an activity–bioavailability balance (ABB) because it includes the following two criteria: ABB= 1 / gm MIC ( drug candidate ) 1 /gm MIC ( ciprofloxacin ) · F calc \( drug candidate \) F calc ( ciproflaxacin ) . The in vitro activity of a group of 4′ N ‐alkyl‐ciprofloxacin derivatives was determined together with that of ciprofloxacin, initially against some reference strains and subsequently against 159 clinical isolates of eight selected species. The inverse of the geometric mean of the lowest concentrati…

Determination of quinolone residues in chicken and fish by capillary electrophoresis-mass spectrometry

2006

A specific pressure-assisted CE-MS method is described for the analysis of five quinolone residues. MS using a single quadrupole is compared with multiple-stage MS using a quadrupole IT (QIT-MS(n)). The procedure involves a common sample preparation by SPE on disposable cartridges. The most suitable electrolyte is 60 mM (NH(4))(2)CO(3) at pH 9.2. Single quadrupole does not provide enough fragmentation to confirm identities according to the current legislation. However, QIT-MS(n) achieves selective fragmentation. Using this method, danofloxacin, enrofloxacin, flumequine, ofloxacin, and pipemidic acid are analyzed in fortified samples of chicken and fish. Recoveries at levels of 50 ng/g were …

Induction of Secondary Metabolites from the Marine-Derived Fungus Aspergillus versicolor through Co-cultivation with Bacillus subtilis

2019

AbstractA new cyclic pentapeptide, cotteslosin C (1), a new aflaquinolone, 22-epi-aflaquinolone B (3), and two new anthraquinones (9 and 10), along with thirty known compounds (2, 4 – 8, 11 – 34) were isolated from a co-culture of the sponge-associated fungus Aspergillus versicolor with Bacillus subtilis. The new metabolites were only detected in the co-culture extract, but not when the fungus was grown under axenic conditions. Furthermore, the co-culture extract exhibited an enhanced accumulation of the known constituents versicolorin B (14), averufin (16), and sterigmatocyctin (19) by factors of 1.5, 2.0, and 4.7, respectively, compared to the axenic fungal culture. The structures of the …

The application of phospholipid removal columns and ultra-high performance liquid chromatography-tandem quadrupole mass spectrometry for quantificati…

2016

In this study a robust and sensitive method based on a proposed sample purification procedure, using zirconia-coated Phree™ columns and analysis by ultra-high performance liquid chromatography with triple quadrupole tandem mass spectrometry are presented for the assessment of multi-class antibiotics in farmed fish species. The sample preparation procedure benefited from combined precipitation of proteins and selective removal of phospholipids by Phree™ columns, resulting in a high sensitivity of the method (LOQ 0.3-9mgkg(-1)). The in-house validation results (precision, repeatability, decision limit CCα, detection capability CCβ, etc.) indicate that the elaborated method is fully suitable f…

Inhalable nano into micro dry powders for ivacaftor delivery: The role of mannitol and cysteamine as mucus-active agents.

2020

In this paper the innovative approach of Nano into micro (NiM9 was developed to produce Nanoparticles loaded Ivacaftor to incorporate into mannitol or mannitol/cysteamine micromatrices for drug pulmonary administration in CF. Nanoparticles composed by a mixture of two polyhydrohydroxyethtylaspartamide copolymers containing a loading of Ivacaftor of 15.5 % w/w were produced. These Nanoparticles were incorporated into microparticles to obtain NiM that were characterized in terms of size and size distribution, interaction with CF-AM by rheological and turbidimetric studies as well as by aerodynamic diameter measurements. Finally the activity of Ivacaftor into these NiM was evaluated by in vitr…

Mechanisms of quinolone resistance in Aeromonas species isolated from humans, water and eels.

2009

Mechanisms of resistance were determined in 33 quinolone-resistant isolates of the species Aeromonas hydrophila, Aeromonas caviae, Aeromonas media, Aeromonas salmonicida, Aeromonas popoffii and Aeromonas veronii, recovered from humans, freshwater and eels. The quinolone resistance-determining regions (QRDRs) of gyrA and parC genes were sequenced in these resistant strains, as well as in 8 quinolone-sensitive Aeromonas used as controls. All quinolone-resistant Aeromonas carried point mutations in the gyrA QRDR at codon 83, respectively giving rise to substitutions Ser(83)-->Ile (32 strains) or Ser(83)-->Val (1 strain). Almost half of these isolates (48%) carried additional point mutations in…

Spontaneous Quinolone Resistance in the Zoonotic Serovar of Vibrio vulnificus

2009

ABSTRACT This work demonstrates that Vibrio vulnificus biotype 2, serovar E, an eel pathogen able to infect humans, can become resistant to quinolone by specific mutations in gyrA (substitution of isoleucine for serine at position 83) and to some fluoroquinolones by additional mutations in parC (substitution of lysine for serine at position 85). Thus, to avoid the selection of resistant strains that are potentially pathogenic for humans, antibiotics other than quinolones must be used to treat vibriosis on farms.