Determination of pKa values of quinolones from mobility and spectroscopic data obtained by capillary electrophoresis and a diode array detector

Jiménez-Lozano, E; Marqués, I.; Barrón, D.; Beltrán, José Luís; Barbosa, J.

doi:10.1016/s0003-2670(02)00435-x

Cited by 146 publications

(64 citation statements)

References 27 publications

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“…The pK a values of the above types of compounds were mostly determined in aqueous media, but several papers deal with pK a estimation in nonaqueous [15,26] or aqueous-organic solvents [27][28][29]. The most frequently applied detection for CZE estimation of pK a is the direct UV-absorption detection [6,7,9,10,13,[30][31][32]; however, conductometric [12], amperometric [23], and indirect UVabsorption [33] detection schemes have been also used.…”

Section: Introductionmentioning

confidence: 99%

Determination of acid–base dissociation constants of amino‐ and guanidinopurine nucleotide analogs and related compounds by capillary zone electrophoresis

et al. 2006

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CZE has been applied for determination of acid-base dissociation constants (pKa) of ionogenic groups of newly synthesized amino- and (amino)guanidinopurine nucleotide analogs, such as acyclic nucleoside phosphonate, acyclic nucleoside phosphonate diesters and other related compounds. These compounds bear characteristic pharmacophores contained in various important biologically active substances, such as cytostatics and antivirals. The pKa values of ionogenic groups of the above compounds were determined by nonlinear regression analysis of the experimentally measured pH dependence of their effective electrophoretic mobilities. The effective mobilities were measured by CZE performed in series of BGEs in a broad pH range (3.50-11.25), at constant ionic strength (25 mM) and temperature (25 degrees C). pKa values were determined for the protonated guanidinyl group in (amino)guanidino 9-alkylpurines and in (amino)guanidinopurine nucleotide analogs, such as acyclic nucleoside phosphonates and acyclic nucleoside phosphonate diesters, for phosphonic acid to the second dissociation degree (-2) in acyclic nucleoside phosphonates of amino and (amino)guanidino 9-alkylpurines, and for protonated nitrogen in position 1 (N1) of purine moiety in acyclic nucleoside phosphonates of amino 9-alkylpurines. Thermodynamic pKa of protonated guanidinyl group was estimated to be in the range of 7.75-10.32, pKa of phosphonic acid to the second dissociation degree achieved values of 6.64-7.46, and pKa of protonated nitrogen in position 1 of purine was in the range of 4.13-4.89, depending on the structure of the analyzed compounds.

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Section: Introductionmentioning

confidence: 99%

Determination of acid–base dissociation constants of amino‐ and guanidinopurine nucleotide analogs and related compounds by capillary zone electrophoresis

et al. 2006

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“…3. Flumequine and oxolinic acid have pKa values of 6.65 and 6.78, respectively (Jimenez-Lozano et al 2002), whereas the pH in the external medium was measured to be in the range of 7.60 to 7.66. In Atlantic cod plasma, the pH is approximately 7.4.…”

Section: Discussionmentioning

confidence: 99%

Antibiotic uptake by cultured Atlantic cod leucocytes and effect on intracellular Francisella noatunensis subsp. noatunensis replication

Kaldestad¹,

Haugland²,

Rønneseth³

et al. 2014

Dis. Aquat. Org.

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The granuloma disease caused by Francisella noatunensis subsp. noatunensis in farmed Atlantic cod has not been successfully treated by use of antibacterials, even when antibacterial resistance testing indicates a sufficient effect. The reason for this treatment failure may be the intracellular existence of the bacteria within immune cells, mainly macrophages. To investigate the effect of antibacterials on intracellular Francisella replication, we established a protocol for the detection of drugs within Atlantic cod immune cells using high-performance liquid chromatography (HPLC). When the uptake and intracellular concentrations of oxolinic acid and flumequine were analysed in isolated adherent head kidney leucocytes (HKLs) by HPLC, we found that uptake was rapid and the intracellular concentrations reflected the extracellular exposure concentrations. To investigate the effect of the antibacterial compounds on intracellular bacterial replication, adherent HKLs experimentally infected with the bacteria were analysed using flow cytometry and intracellular labelling of bacteria by specific antibodies. We found that flumequine did not inhibit intracellular bacterial replication. Unexpectedly, the results indicated that the intracellularly effiacy of the drug was reduced. The HPLC method used proved to be highly applicable for accurate determination of intracellular drug concentrations. When combined with sensitive and specific flow cytometry analyses for identification and measurement of intracellular bacterial replication, we suggest that this approach can be very valuable for the design of antibacterial treatments of intracellular pathogens.

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“…For sarafloxacin, pK 1 = 5.62 and pK2 = 8.18; for ciprofloxacin pK 1 = 5.86 and pK 2 = 8.24; for enrofloxacin, pK 1 = 5.88 and pK 2 = 7.74; for flumequine, pK 1 = 6.65 [22]. Taking into considerations the pK a values, the effect of pH values from 7 to 9.6 on the separation of the four fluoroquinolones was investigated and the above selected system as the running buffer was further studied.…”

Section: Effect Of Running Buffermentioning

confidence: 99%

Effective Separation and Simultaneous Determination of Four Fluoroquinolones in Milk by CE with SPE

Sun

Zhao

2008

Chroma

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A simple and sensitive capillary electrophoresis method with solid phase extraction was developed for the determination of sarafloxacin, ciprofloxacin, enrofloxacin and flumequine in milk. Solid-phase extraction with Oasis HLB cartridge column was used for the isolation of four fluoroquinolones in raw milk from a farm and fresh milk sample. Separation conditions of CE, including running buffer, voltage and temperature, were investigated and optimized. Baseline separation was achieved for the four fluoroquinolones under the developed conditions. Correlation coefficients greater than 0.9998 were obtained for all fluoroquinolones with a dynamic range from 1 up to 100 mg L -1. The intra-day precision was less than 5%, and the inter-day precision was less than 6%. The method recoveries of four fluoroquinolones were in the range of 70.9-90.6%. The detection limits for sarafloxacin, ciprofloxacin, enrofloxacin and flumequine was 19.8, 15.2, 13.3 and 15.9 lg kg -1

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Determination of pKa values of quinolones from mobility and spectroscopic data obtained by capillary electrophoresis and a diode array detector

Cited by 146 publications

References 27 publications

Determination of acid–base dissociation constants of amino‐ and guanidinopurine nucleotide analogs and related compounds by capillary zone electrophoresis

Determination of acid–base dissociation constants of amino‐ and guanidinopurine nucleotide analogs and related compounds by capillary zone electrophoresis

Antibiotic uptake by cultured Atlantic cod leucocytes and effect on intracellular Francisella noatunensis subsp. noatunensis replication

Effective Separation and Simultaneous Determination of Four Fluoroquinolones in Milk by CE with SPE

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