Stepwise optimization and sensitivity improvement of green micellar electrokinetic chromatography method to simultaneously determine some fluoroquinolones and glucocorticoids present in various binary ophthalmic formulations

A sensitive micellar electrokinetic chromatography method is presented to simultaneously quantify ofloxacin, gatifloxacin, dexamethasone sodium phosphate and prednisolone acetate. The method has the advantages of being rapid, accurate, reproducible, ecologically acceptable and sensitive. The electrophoretic separation utilized 20 mm borate buffer as background electrolyte with pH 10.0 ± 0.1 and 50 mm sodium dodecyl sulfate as a micelle forming molecule. A capillary tube (50 μm i.d., 33 cm) of fused silica was used and on-column diode array detection at 243 nm for dexamethasone sodium phosphate and prednisolone acetate, and 290 nm for ofloxacin and gatifloxacin. Various factors were optimized such as the background electrolyte (type, concentration and pH), addition of sodium dodecyl sulfate and its concentration, detection wavelength, applied voltage and injection parameters. The studied drugs were efficiently separated in 6.2 min, at 20 kV with high resolution. The greenness of the method was estimated using an eco-scale tool and the presented method was found to have excellent green characteristics. The method was validated in conformance with International Conference on Harmonization guidelines, with acceptable accuracy, precision and selectivity. The suggested method can be employed for the economic analysis of the four drugs in dissimilar binary combinations of eye drops saving solvents and chemicals.     

加替沙星-茜素红体系的紫外特性及加替沙星的测定

加替沙星与茜素红反应可形成配合物,使茜素红的紫外吸光度增强,且加替沙星浓度在0.20~110.00mg.L-1范围内与吸光度呈良好的线性关系,以此为基础,建立了测定加替沙星的新方法.将此方法用于片剂、粉针剂和尿液中加替沙星含量的测定,结果与文献报道的荧光法一致.     

An overview of analytical methodologies for the determination of antibiotics in environmental waters

The widespread occurrence of antibiotics as contaminants in the aquatic environment has increased attention in the last years. The concern over the release of antibiotics into the environment is related primarily to the potential for the development of antimicrobial resistance among microorganisms. This article presents an overview of analytical methodologies for the determination of quinolone (Qs) and fluoroquinolone (FQs), macrolide (MLs), tetracycline (TCs), sulfonamide (SAs) antibiotics and trimethoprim (TMP) in different environmental waters. The analysis of these antibiotics has usually been carried out by high-performance liquid chromatography (HPLC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) and to a lesser extent by ultraviolet (UV) or fluorescence detection (FD). A very important step before LC analysis is sample preparation and extraction leading to elimination of interferences and prevention of matrix effect and preconcentration of target analytes.     

Development of novel graphene-like layered hexagonal boron nitride for adsorptive removal of antibiotic gatifloxacin from aqueous solution

Graphene-like layered hexagonal boron nitride (g-BN) was prepared and characterized. The performance of using g-BN as an adsorbent for removal of fluoroquinolone antibiotic gatifloxacin (GTF) from aqueous solution was evaluated. g-BN showed an excellent adsorption capability with notable GTF adsorption ratio of more than 90%. Data of equilibrium adsorption of GTF onto g-BN at different temperatures were represented by Langmuir, Freundlich and Tempkin isotherm models, and Langmuir exhibited the best fitting with the maximum adsorption capacity of 88.5 mg·g^?1 at 288 K. GTF adsorption was insignificantly affected by solution pH. Competitive role of Na⁺ and Ca²⁺ in the solution inhibited the adsorption of GTF and decreased the adsorption capacity a bit. The adsorption process was spontaneous and exothermic. The adsorption was probably governed by π–π interaction between GTF and g-BN, and electrostatic interaction may also exist in the adsorption process.     

吖啶红褪色光度法测定加替沙星的含量

加替沙星(Gatifloxacin)是由日本杏林制药公司最早开发研制,1999年12月BMS公司在美国首次上市的氟喹诺酮类抗菌药,该药具有抗菌谱广、抗菌活性强、光毒性低等特点,对革兰氏阴性菌和革兰氏阳性菌均有较好的疗效,主要用于呼吸道感染、泌尿道感染、皮肤和软组织感染等的治疗。目前     

Chemiluminescent Detection of Gatifloxacin Residue in Milk

Abstract

An indirect competitive chemiluminescent enzyme-linked immunosorbent assay (CL-ELISA) for detection of gatifloxacin residue in milk was developed in this study. Compared with conventional colorimetric ELISA using the same antibody, the developed CL immunoassay shows a significant improvement in sensitivity and detectability with an IC₅₀ of 0.4 ng mL^?1 and a detection limit of 0.001 ng mL^?1 and thus is suitable to be used as a highly sensitive screening method to detect and regulate illegal use of gatifloxacin in food and food products. The test kit was applied to detect milk samples spiked by gatifloxacin, and satisfactory results were obtained.     

Gatifloxacin-铕荧光探针测定DNA

在pH 7.0±0.1的Tris-HCl缓冲溶液中,Eu3 与加替沙星形成的络合物受270 nm紫外光激发发出Eu3 的特征荧光峰,加人脱氧核糖核酸(DNA)能大大增强体系的荧光强度,由此建立GFLX-Eu3 络合物探针测定核酸的方法.与GFLX-Eu3 二元络合物相比.GFLX-Eu3 -DNA三元体系荧光强度显著增强,且最大吸收波长紫移5 nm,表明形成三元络合物.研究了反应的最佳条件,并初步探讨了GFLX-Eu3 络合物探针和DNA结合机制.     

Development and validation of a HPLC method for simultaneous quantitation of gatifloxacin, sparfloxacin and moxifloxacin using levofloxacin as internal standard in human plasma: application to a clinical pharmacokinetic study

A highly selective, sensitive and accurate HPLC method has been developed and validated for the estimation of three fluoroquinolones (FQs) viz., gatifloxacin (GFC), sparfloxacin (SFC) and moxifloxacin (MFC) with 500 microL human plasma using levofloxacin (LFC) as an internal standard (IS). The sample preparation involved simple liquid-liquid extraction of GFC, SFC, MFC and IS from human plasma with ethyl acetate. The resolution of peaks was achieved with phosphate buffer (pH 2.5)-acetonitrile (80:20, v/v) at a flow rate of 1 mL/min on a Kromasil C(18) column. The total chromatographic run time was 18.0 min and the simultaneous elution of GFC, SFC, MFC and IS occurred at approximately 10.8, 12.8, 17.0 and 6.0 min, respectively. The method proved to be accurate and precise at linearity range of 100-10,000 ng/mL with a correlation coefficient (r) of > or =0.999. The limit of quantitation for each of the FQs studied was 100 ng/mL. The intra- and inter-day precision and accuracy values found to be within the assay variability limits as per the FDA guidelines. The developed assay method was applied to a pharmacokinetic study in human volunteers following oral administration of 400 mg GFC tablet.     

Pulse radiolysis study on gatifloxacin——A fluoroquinolone antibiotic

The reactions between gatifloxacin(GFX) and various one-electron oxidants,such as ˙OH,N3˙,Br2˙ˉ,and SO4˙ˉ,have been studied by pulse radiolysis techniques.The GFX radical anion formed in the reaction of GFX with eaqˉ could either be protonated or deprotonated,and the absorption of GFX radical anion was located at 390 nm.The transient species produced by the reaction of GFX with ˙OH radical shows a broad band in the 380?600 nm region with a shoulder,while the oxidation by N3˙,SO4˙ˉ,and Br2˙ˉ results in an absorption band with λmax = 370 nm.At neutral condition(pH 7),the rate constants of GFX reacting with ˙OH,N3˙,Br2˙ˉ,SO4˙ˉ and eaqˉ are estimated to be 1.0 × 1010,3.1 × 109,2.8 × 109,3.0 × 109,and 1.8 × 1010 dm3 mol?1 s?1,respectively.From the pH dependence on the formation of electron adducts and on the rate constant of GFX with eaqˉ,the pKa of GFX radical anion is estimated to be 5.5 and 9.3.     

盐酸加替沙星的合成研究

以2,4,5-三氟-3-甲氧基苯甲酸为起始原料,经酰氯化后与N,N-二甲氨基丙烯酸乙酯偶联,环丙胺置换、环合水解、与2-甲基哌嗪缩合、水解成盐制得本品,总收率为41.1%.本合成工艺原料易得,操作简单,是一种新的合成加替沙星的方法.