Separation and determination of seven fluoroquinolones by pressurized capillary electrochromatography

In this paper, pressurized CEC was used for the separation and determination of seven fluoroquinolones (FQs). The effect of different experimental conditions, such as the concentration and pH of the buffer, the organic modifier concentration, the surfactant and ion-paring agents added to the electrolyte, and applied voltage were studied. All the seven FQs were baseline separated using mobile phase containing 27% v/v ACN, 5 mmol/L Na2HPO4 buffer (pH 4.0 adjusted using citric acid), 11 mmol/L SDS, and 0.01% TEA v/v at detection wavelength of 287 nm and at an applied voltage of -10 kV. The calibration curves were linear (r>0.9991) over a concentration range of 1.0-50.0 mg/L for norfloxacin (NFLX); 2.5-50.0 mg/L for fleroxacin (FLX), ciprofloxacin (CPFX), and lomefloxacin (LMX); and 5.0-50.0 mg/L for enoxacin (ENX), ofloxacin (OFLX), and gatifloxacin (GFLX). The detection limits (S/N = 3) for ENX, OFLX, FLX, NFLX, CPFX, LMX, and GFLX were 0.5, 0.8, 0.4, 0.2, 0.4, 0.5, and 1.0 mg/L, respectively. The method is simple, rapid, and reproducible. It was successfully applied to the analysis of fish muscle samples spiked with FQs. Mean recoveries ranged from 81.6 to 97.6%.     

荷移光度法测定依诺沙星

依诺沙星与茜素红在水-乙醇介质中发生电荷转移反应,其中依诺沙星是电子给予体,茜素红是电子接受体,依据此荷移反应建立了一种快速测定依诺沙星的荷移分光光度法.荷移络合物在 546 nm 波长处有最大吸收,表观摩尔吸光率为 8.04×103L·mol-1·cm-1,相关系数为0.999 9.该络合物的组成为 1:1,表观稳定常数为 2.84×104.依诺沙星的质量浓度在 0～40 mg·L-1范围内服从比耳定律.当依诺沙星的质量浓度为 20 mg·L-1时,测定结果的相对标准偏差(n=6)为 1.2%,回收率在 99%以上.测定了依诺沙星制剂中有效成分的含量,与文献[1]方法结果基本吻合.     

Chemical Modification of EVA for DrugRelease Application

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Determination of fluoroquinolones in urine and serum by using high performance liquid chromatography and multiemission scan fluorimetric detection

A high performance liquid chromatography (HPLC) method has been developed for the simultaneous determination of four fluoroquinolones. The studied compounds have been enoxacin (ENO), norfloxacin (NOR), ofloxacin (OFLO) and enrofloxacin (ENRO). An isocratic elution method, using a mixture of tetrahydrofuran (8%) and phosphate buffer (pH 3.00, 30.0 mM, 92%) as mobile phase, has been developed. Fluorimetric detection, exciting at 277 nm, and multiemission scan (407 nm for ENO, 444 nm for both NOR and ENRO and 490 nm for OFLO) has been used. Detection limits of 500, 14.7, 25.2 and 15.0 ng mL⁻¹ for ENO, NOR, OFLO and ENRO, respectively, have been obtained. The proposed method has been satisfactorily applied to analyze NOR, OFLO and ENRO in human urine and serum samples.     

Simultaneous Determination of Trace Ofloxacin and Enoxacin by TLC-Fluorescence Spectrodensitometry

Abstract

A new TLC-fluorescence spectrodensitometry method is described for the simultaneous determination of trace ofloxacin and enoxacin, using a optimized mobile phase of chloroformmethanolethyl acetatetetrahydrofuranaqueous ammonia (6:4.6:1.5:0.8:1.5, V/V). The influence of the silica gel plates previously treated with various concentrations of sodium edetate solution in various pH's are studied. Their R, values are 0.54 and 0.29 respectively. The excitation, wavelength is 335nm. The linear ranges are 0~75ng. The relative standard deviations are <6.9%. The mean recovery of the two antibiotics in body fluid ranged from 95.4% to 105.2%.     

衍生化分光光度法测定依诺沙星和诺氟沙星

碱性介质中,依诺沙星和诺氟沙星均能与1,2-萘醌-4-磺酸钠(NQS)发生反应而生成橙红色的物质,并使最大吸收波长发生大幅度的红移。据此建立了测定这两种药物的分光光度新方法。依诺沙星和诺氟沙星的浓度分别在0.8~16 mg.L-1和0.9~18 mg.L-1范围内符合比耳定律;衍生物在454 nm和462 nm波长处的表观摩尔吸光系数分别为1.86×104L.mol-1.cm-1和1.93×104L.mol-1.cm-1;两种药物的检出限分别为0.13 mg.L-1和0.19 mg.L-1。该方法已成功用于药物制剂中依诺沙星和诺氟沙星含量的测定。其回收率为96.63%~99.55%,相对标准偏差为0.56%~0.89%。     

Sensitive determination of enoxacin by its enhancement effect on the fluorescence of terbium(III)-sodium dodecylbenzene sulfonate and its luminescence mechanism

The fluorescence system of enoxacin-Tb³⁺-sodium dodecylbenzene sulfonate (SDBS) was investigated in this paper. The experiments indicated that the fluorescence intensity of Tb³⁺-SDBS was greatly enhanced by enoxacin. Accordingly, a sensitive fluorimetric method for determining enoxacin was established. The fluorescence intensity was measured by a 1-cm quartz cell with an excitation wavelength of 290 nm and an emission wavelength of 545 nm. The enhanced fluorescence intensity of the system (ΔF) showed a good linear relationship with the concentration of enoxacin in the range of 5.0×10⁻⁹ to 2.0×10⁻⁶ mol L⁻¹, its correlation coefficient was 0.9992 and the detection limit (S/N=3) was 2.8×10⁻⁹ mol L⁻¹. The presented method was used to determine enoxacin in real pharmaceutical samples. The luminescence mechanism was also discussed in detail. In the fluorescence system of enoxacin-Tb³⁺-SDBS, SDBS not only acted as the surfactant but also acted as the energy donor.     

依诺沙星与铁配合物的合成、表征及其生物活性

由水热法合成了依诺沙星铁配合物,用固体培养基平板药敏试验方法测定了配合物的体外抗菌活性。结果表明,合成的依诺沙星铁配合物对金黄色葡萄球菌、肺炎链球菌、绿脓杆菌、白色念珠菌都具有抗菌活性,但只有对金黄色葡萄球菌和绿脓杆菌的抗菌活性强于配体本身。     

Enoxacin—Tb3+ Complex as an Environmentally Friendly Fluorescence Probe for Coenzyme A and Its Application

Abstract

A new spectrofluorimetric method was developed for the determination of trace amounts of coenzyme A using enoxacin–Tb³⁺ as a fluorescent probe. In the presence of periodic acid (H₅IO₆), coenzyme A could remarkably enhance the fluorescence intensity of the Tb³⁺–enoxacin complex at 545 nm at pH 5.4. The optimal conditions for the determination of coenzyme A were also investigated. This method could be successfully applied to assess coenzyme A in injection and biological samples. Moreover, the enhancement mechanism of the fluorescence intensity of the coenzyme A–Tb³⁺–enoxacin system in the presence of H₅IO₆ was also discussed.