Fluoroquinolones , detection

GC-MS is applied in some methods for the analysis of pharmaceuticals in sludge [45, 109]. However, this technique can only be successfully applied for a limited number of nonpolar and volatile pharmaceutical compounds, while analysis of polar pharmaceuticals requires a time-consuming and often irreproducible deriva-tization. Consequently, LC-MS is the preferred technique in many laboratories. Some other detection techniques are also employed, such as diode array (DAD) and electrochemical (ED) and fluorescence detection (ELD). In the case of fluoroquinolones, ELD is still the favored technique. 

Macrolide antibiotics (clarithromycin, dehydroerythromycin, etc.) and sulfonamides (sulfamethoxazole, sulfadimethoxine, sulfamethazine, and sulfathi-azole) are the most prevalent antibiotics found in the environment with levels around a few micrograms per liter, whereas fluoroquinolones, tetracyclines, and penicillins have been detected in fewer cases and usually at low concentrations (nanograms per liter) [3,20,23,72]. This result is not surprising, since penicillins are easily hydrolyzed and tetracyclines readily precipitate with cations such as calcium and are accumulated in sewage sludge or sediments. Several reviews have reported the environmental occurrence of different antibiotics in aquatic and soil compartments. Some of these data are detailed in Table 1. 

We have found only one attempt to use immunoassays to detect sulfonamides in environmental samples. As in the case of penicillins and tetracyclines and also for fluoroquinolones (see below), Campagnolo et al. [84] measured sulfonamides in water samples proximal to a farm in Iowa using a commercial Charm II RIA test, accomplishing a LOD of 5 pg L 1 for sulfamethazine. 

Snitkoff et al. [75] reported the development of an EIA for the detection of ciprofloxacin in serum, which was sensitive at picogram per milliliter levels of the antibiotic and no cross-reaction with its metabolites was observed. Gobbo et al. [118] recently described the production of PAb for ciprofloxacin with the aim of detecting fluoroquinolones in Brazilian livestock. On the other hand, Bucknall et al. [77] produced antibodies for quinolones and fluoroquinolones with the aim of developing both generic and specific immunoassays. ELISAs for ciprofloxacin, enrofloxacin, flumequine, and nalidixic acid were developed with sensitivity values around 4 pg kg 1 (on both the generic and specific assays) in bovine milk and ovine kidney. 

We have only found one example of the application of an immunoassay kit to the analysis of fluoroquinolones in environmental samples [84]. The assay is able to detect enrofloxcin as standard analyte with sensitivity levels of 5 pg L1. 

The data on the adverse reactions of the fluoroquinolones which have received the most extensive clinical evaluation (ciprofloxacin, ofloxacin, pefloxacin, norfloxacin and enoxacin), involving about 30,000 patients, have been the subject of a review [54a], An important point noted in this review involves the difficulty in detecting an important severe adverse reaction if it is of relatively low frequency, until there has been a very large patient exposure (some examples are provided in which at least 150,000-300,000 exposures would be required to observe the importance of side-effects, resulting in an alert, which have been discovered with specific drugs). However, the majority of side-effects observed thus far with the fluoroquinolones have been minor,... 

Seifrtova M, Pena A, Lino CM et al (2008) Determination of fluoroquinolone antibiotics in hospital and municipal wastewaters in Coimbra by liquid chromatography with a monolithic column and fluorescence detection. Anal Bioanal Chem 391 799-805... 

Nakata H, Kannan K, Jones PD (2005) Determination of fluoroquinolone antibiotics in wastewater effluents by liquid chromatography and fluorescence detection. Chemosphere 58 759-766... 

Golet E.M., A.C. Alder, A. Hartmann, T.A. Temes, and W. Giger (2001). Trace determination of fluoroquinolone antibacterial agents in urban wastewater by sohd-phase extraction and liquid chromatography with fluorescence detection. Analytical Chemistry 73 3632-3638. 

However, recent investigations on the effect of the tissue matrix on the detection limits attained by this test have indicated that ceftiofur, sulfonamides, streptomycin, and some macrolide antibiotics cannot be detected in intact meat with the plates and the bacterial strains prescribed in the European four-plate test (81, 82). Two plates of this system were not found suitable for screening sulfamethazine or streptomycin at levels far above the MRL the third plate detected tetracyclines and -lactams up to the MRL levels whereas the fourth was sensitive to -lactams and some but not all macrolides. Detection, on the other hand, of the fluoroquinolones enrofloxacin and ciprofloxacin could only be made possible by an additional Escherichia coli plate not included in the four-plate test. 

RJ Maxwell, E Cohen. Comparison of programmable versus single-wavelength fluorescence for the detection of 3 fluoroquinolone antibacterials isolated from fortified chicken liver using coupled on line microdialysis and HPLC. HRC-J High Resolution Chromatogr 21 241-244, 1998. 

In recent years antibiotics residues have accumulated in different environmental compartments. Fluoroquinolone antibiotics are strongly adsorbed by soil, and therefore their extraction requires exhaustive procedures, leading to complex extracts due to coextraction. Despite this the authors succeeded in selectively detecting the fluoroquinolones from crude soil extracts directly injected onto an MIP HPLC column and using UV detection [Fig. 2 (Fig. 6 of the original)]. Recoveries close to 100% were obtained for five fluoroquinolones. The analysis time was only a few minutes, so this method was found suitable for screening soil samples for the presence of fluoroquinolones. The individual fluoroquinolones were not resolved on the column. 

Cohen, E., R.J. Maxwell, and D.J. Donoghue. 1999. Automated multi-residue isolation of fluoroquinolone antimicrobials from fortified and incurred chicken liver using on-line microdialysis and high-performance liquid chromatography with programmable fluorescence detection. J. Chromatogr. B 724 137-145. 

Pinacho, D.G., F. Sanchez-Baeza, and M.P. Marco. 2009. Development of a class selective indirect competitive enzyme-linked immunosorbent assay (ELISA) for detection of fluoroquinolone antibiotics. J. Agric. Food Chem. submitted. 

Rizk et al. developed a sensitive and selective derivative UV-spectrophotometric method for the determination of three fluoroquinolone compounds, including ciprofloxacin, in formulations and spiked biological fluids (7]. The method depends on the complexation of Cu(II) with the studied compounds in an aqueous medium. A linear correlation was established between the amplitude of the peak and the drug concentration over the range of 35-120 ng/mL. The detection limit was reported as 1.3 ng/mL. The method was used for the determination of the ciprofloxacin bulk drug substance and its tablet formulation, with an overall percentage recovery of 99.22 0.55 to 100.33 1.60. 

Aly et al. [16] reported a rapid and sensitive chemiluminescence (CL) method for the determination of three fluoroquinolone derivatives, including ciprofloxacin, in both pharmaceutical dosage forms and in biological fluids. The method is based on the CL reaction of the drugs with tris(2,2 -bipyridyl)ruthenium(II) and cerium(IV) in sulfuric acid medium. The CL intensity was proportional to the concentration of ciprofloxacin in solution over the range 0.05-6 pg/mL, and the limit of detection was reported to be 26 nM. 

Holtzapple et al. developed an immunoassay method for determination of four fluoroquinolone compounds (including ciprofloxacin) in liver extracts [64]. In this method, an immunoaffinity capture SPE column was used, that contained anti-sarafloxacin antibodies covalently cross-linked to protein G. After interfering liver matrix compounds had been washed away, the bound ciprofloxacin was eluted directly onto the HPLC column. The HPLC system used a 5 pm Inertsil phenyl column (15 cm x 4.6 mm i.d.), with 0.1 M-glycine hydrochloride/acetonitrile (17 3) as the mobile phase (eluted at a rate of 0.7 mL/min). Fluorimetric detection at 444 nm was used after excitation at 280 nm. The recovery of ciprofloxacin ranged from 85.7 to 93.5%, and the detection limit was... 

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