Determination Of Norfloxacin Research Articles

Cloud Point Extraction Spectrophotometric Method for Mutual Determination of Norfloxacin and Iron(III) in Human Serum and Drug Formulations

An eco-friendly procedure was developed for dual detection of drug norfloxacin (NOR) and iron(III) ions in biological and pharmaceutical samples via the coupling of cloud-point extraction procedure with molecular spectrophotometry. The drug norfloxacin reacts with Fe(III) ions in dilute acidic medium to form a colored hydrophobic (Fe(III)-NOR) complex which initially extracted into micelles of Triton x-114 as a mediated extractant followed the determination of both NOR and Fe(III) ions individually, by using spectrophotometry at same wavelength maximum of 432 nm. To achieve this goal, all experimental variables for both target analytes were previously optimized. The results have shown that the preconcentration factors of 83 and 71 for NOR and Fe(II) leading to achieve a limit of detection of 0.692 μg mL -1 3.42 ng mL -1 with linear range of 2.5- 125 μgmL -1 (r= 0.9998) and 5-150 ng mL -1 (r=0.9997) respectively. The mean recovery percentage of 98.95±1.09% and 98.77±2.29%; the precision (RSD%) ranged between 0.04-0.66% and 0.59- 0.97% were obtained for NOR and Fe(III) respectively. The proposed method was used for the determination of NOR in the serum samples of different subjects orally administration for two hours with Norfloxacin tablets BP 400 mg, in addition to drug formulations like Norflox Eye/Ear drops, While iron was determined in four selected drug formulations and in both cases, the experimental values are agreed with the quoted values that stated by the manufacturer company,

Convenient and sensitive detection of norfloxacin with fluorescent carbon dots.

Carbon dots (CDs) were synthesized by refluxing glucose, as efficient fluorescence probes, which show convenient and sensitive detection of norfloxacin (NOR) over a wide concentration range. It is worth noting that because of the hydrogen bond interactions between the CDs and NOR, the fluorescence intensity of CDs was remarkably enhanced in the presence of NOR, which indicates that CDs are capable of rapid, stable and sensitive determination of NOR. Compared with high-performance liquid chromatography, the fluorescence enhancement method is considerably simpler and faster, and will pave a new way for the determination of NOR.

Direct determination of antibacterial norfloxacin in urine by isopotential fluorimetry

A novel and simple method is presented for the determination of norfloxacin in human urine by matrix isopotential synchronous fluorescence spectrometry (MISF). This method is useful for the determination of compounds in samples with unknown background fluorescence, such as norfloxacin in urine, without the need for tedious sample pre-treatment. The method was performed in ethanol-water medium (10% v/v), at an apparent pH of 4.8 provided by adding sodium acetate-acetic acid buffer solution. In the determination of norfloxacin in urine the fluorescent intensity varied linearly with its concentration from 20 to 200 ng/mL. An exhaustive statistical analysis has been developed to all calibration graphs, this treatment includes robust regression such as least median of squares, which also detects outliers and leverage points. The overall least-squares regression has been applied to find the more exact straight line that fits the experimental data. The error propagation has been considered to calculate the detection limit and the repeatability of the method. The method shows very low detection limits with acceptable recoveries and precisions. The applicability of the proposed method was illustrated in the determination of norfloxacin in human urine sample without sample pre-treatment.

Determination of Norfloxacin and Ciprofloxacin in Chicken Meat Based on Matrix Solid-Phase Dispersion Extraction and Capillary Zone Electrophoresis

This study describes an effective matrix solid-phase dispersion (MSPD) extraction method for determining norfloxacin (NOR) and ciprofloxacin (CIP) in chicken meat by capillary zone electrophoresis (CZE). The optimum conditions for separating NOR and CIP were as follows:60 cm×75 μm i.d. capillary, 40 mmol L−1borate buffer solution (pH 8.5), separation voltage at 16 kV, and detection wavelength at 280 nm. Before CZE determination, the chicken meat samples were purified and enriched by using an MSPD extraction step with a preconditioned C18cartridge and by eluting the compound with 3.0 mL of acetonitrile. A good linear fit curve with the concentration range of 0.10 μg g−1to 500 μg g−1for NOR and CIP was obtained, with regression coefficients of 0.9994 and 0.9986, respectively. The limits of detection of NOR and CIP were 0.04 and 0.03 μg g−1, respectively. The proposed method was successfully applied to determine NOR and CIP in chicken meat.

A simple method for the determination of fluoroquinolone residues in tilapia (Oreochromis niloticus) and pacu (Piaractus mesopotamicus) employing LC-MS/MS QToF

The use of antimicrobials in livestock production is a powerful resource applied throughout the world to guarantee high yield and control bacterial diseases in aquaculture. However, residues of these substances in animal products represent a potential risk to consumer health when residue levels are above the established maximum residue limits (MRLs). Fluoroquinolones (FQs) are antimicrobials commonly used worldwide in aquaculture. The aim of this work was to develop and validate a simple analytical method for the simultaneous determination of norfloxacin, danofloxacin, enrofloxacin and ciprofloxacin levels in tilapia (Oreochromis niloticus) and pacu (Piaractus mesopotamicus) fillets using liquid chromatography–tandem mass spectrometry (LC-MS/MS) quadrupole time of flight (QToF). The FQs were extracted from the fillets with 1% acetic acid–methanol and 1% acetic acid–acetonitrile solutions using ultrasonic assistance. The clean-up was performed with hexane. Chromatographic separation was conducted in an XTerra RP18 column (2.1 × 150 mm, 5 µm) at 25 °C with a flow of 0.2 mL min−1. The mobile phase consisted of 0.1% aqueous formic acid and acetonitrile, with gradient elution. The validation parameters for all FQs were linearity (>0.99), intra-day precision (CV of 1%–9%), inter-day precision (CV of 3%–17%), decision limit (63–126 ng g−1), detection capability (76 –152 ng g−1) and accuracy (90%–111%). The limit of quantification was lower than the MRL for each FQ, indicating that the method is suitable for the determination of the FQ levels in the fish fillets. The mass analyser of the QToF type was able to confirm the identities of the FQs with an error of the accuracy of the mass (reasons m/z) of less than 10 ppm.

Development and Validation of a Simple, Rapid and Stability-Indicating High Performance Liquid Chromatography Method for Quantification of Norfloxacin in a Pharmaceutical Product

A stability-indication high performance liquid chromatographic method has been developed for the determination of norfloxacin in tablet dosage forms. Optimum separation was achieved in less than 7 minutes using Eclipse Plus Zorbax C18 Agilent, 150 mm×4.6 mm i.d., 5 μm particle size column. The analyte was resolved by using a mobile phase 5% acetic acid aqueous solution and methanol (80:20, v/v) at a flow rate 1.0 ml/min on an isocratic high performance liquid chromatographic system at a wavelength of 277 nm. Linearity, system suitability, precision, sensitivity, selectivity, specific, and robustness were established by International Conference Harmonization guidelines. For stress studies the drug was subjected to photolysis, oxidation, acid, alkaline and neutral conditions. The analytical conditions and the solvent developed provided good resolution within a short analysis time and economic advantages. The proposed method not required sophisticated and expensive instrumentation.

Electrochemical sensor for the sensitive determination of norfloxacin in human urine and pharmaceuticals

Electrochemical determination of Norfloxacin (NF) has been presented at edge plane (EPPGS) and basal plane pyrolytic graphite sensors (BPPGS) by using square wave voltammetry at physiological pH 7.2. An increased peak current with a shift of peak potential to less positive value was observed at EPPGS as compared to BPPGS. The effect of pH, scan rate and analyte concentration has been examined. The peak current was found to be linear to the concentration of NF in the range 0.5 × 10 − 6 to 50.0 × 10 − 6 mol L − 1 for EPPGS and the detection limit (3σ/b) was found to be 28.3 × 10 − 8 mol L − 1 . The method has been successfully used to determine the content of NF in the pharmaceutical preparations. Biological relevance of the developed method has been described by the determination of NF in human urine samples of the patients undergoing treatment with NF. The method is selective and NF can be determined without any interference from common urine metabolites such as uric acid and ascorbic acid.

Development and validation of a fast isocratic liquid chromatography method for the simultaneous determination of norfloxacin, lomefloxacin and ciprofloxacin in human plasma

A simple and fast liquid chromatographic method coupled with fluorescence detection (LC-FD) is reported, for the first time, for the simultaneous quantification of norfloxacin (NOR), ciprofloxacin (CIP) and lomefloxacin (LOM) in human plasma, using levofloxacin as internal standard (IS). Sample preparation consists of a single-step precipitation of plasma proteins followed by vortex-mixing and centrifugation. Chromatographic separation was achieved within 7 min on a reversed-phase C(18) column with a mobile phase consisting of 0.1% aqueous formic acid (pH = 3.0, triethylamine)-methanol (82:18, v/v) pumped isocratically at 1.2 mL/min. The detector was set at excitation/emission wavelengths of 278/450 nm. Calibration curves were linear (r(2) ≥ 0.994) in the range of 0.02-5.0 µg/mL, and the limit of quantification was established at 0.02 µg/mL for all analytes (NOR, CIP and LOM). The overall precision did not exceed 8.19% and accuracy was within ±10.91%. NOR, CIP and LOM were extracted from human plasma with an overall mean recovery ranged from 90.1 to 111.5%. No interferences were observed at the retention times of the analytes and IS. This novel LC-FD method enables the reliable determination of NOR, CIP and LOM in a single chromatographic run, which may be suitable to support human pharmacokinetic-based studies with those antimicrobial agents.

Peroxyoxalate Photoinduced Chemiluminescence Detection of Norfloxacin in Pharmaceutical Products by Flow Injection Analysis

A new method for the determination of norfloxacin by flow injection analysis based on photoinduced chemiluminescence detection is proposed. We have selected the peroxyoxalate (PO) reaction based on the possibility of detecting fluorescent products derived from a photochemically induced decomposition of norfloxacin, observing high signal when the derivative participates in the reaction. A FIA device, with two-injection valves for the introduction of both the PO and the photodecomposed analyte solutions in the flow system, has been used, avoiding the problems arising from the use of organic solvents. The method was applied to the monitoring of norfloxacin in pharmaceuticals.

Novel selective kinetic spectrophotometric method for determination of norfloxacin in its pharmaceutical formulations

Novel selective and simple kinetic spectrophotometric method has been developed and validated for the determination of norfloxacin (NOR) in its pharmaceutical formulations. The method was based on the reaction of N-vinylpiprazine formed from the interaction of the mono-substituted piprazinyl group in NOR and acetaldehyde with 2,3,5,6-tetrachloro-1,4-benzoquinone to give colored N-vinylpiprazino-substituted benzoquinone derivative. The formation of the colored product was monitored spectrophotometrically by measuring the absorbance at 625 nm. The factors affecting the reaction was studied and optimized. The stoichiometry of the reaction was determined and the reaction pathway was postulated. The activation energy of the reaction was calculated and found to be 5.072 kJ mol −1. The initial rate and fixed time (at 5 min) methods were utilized for constructing the calibration graphs. The graphs were linear in concentration ranges of 20–150 and 10–180 μg mL −1 with limits of detection of 8.4 and 3.2 μg mL −1 for the initial rate and fixed time methods, respectively. The analytical performance of both methods was fully validated, and the results were satisfactory. No interferences were observed from the excipients that are commonly present in the pharmaceutical formulations, as well as from tinidazole that is co-formulated with NOR in some of its formulations. The proposed methods were successfully applied to the determination of NOR in its commercial pharmaceutical formulations. The label claim percentages were 98.4–100.4 ± 0.52–1.04%. Statistical comparison of the results with those of the official method showed excellent agreement and proved that there was no significant difference in the accuracy and precision between the official and the proposed methods.

Chemiluminescence mechanisms of cerium-norfloxacin and its application in urine analysis

AbstractIn this article, novel chemiluminescence mechanisms between norfloxacin and cerium(IV) in an acidic medium were studied. Chemiluminescence spectra of the present system were recorded observing three maximum emissions at about 475 nm, 550 nm, and 620 nm, respectively. The results indicate that the chemiluminescence peaks located at 475 nm and 620 nm can be ascribed to the emission of a singlet oxygen, while the chemiluminescence emission at 550 nm occurred in course of the reaction between acidic cerium(IV) and the phenolic intermediate. Under optimum conditions, the chemiluminescence intensity was linear with the concentration of norfloxacin over the range of 2.0 × 10−8−1.0 × 10−5 g mL−1 and the detection limit of 1.0 × 10−8 g mL−1 (S/N = 3). The relative standard deviation was 1.94 % for a 4.0 × 10−7 g mL−1 norfloxacin solution considering eleven repeated measurements. The present chemiluminescence system was successfully applied in the determination of norfloxacin in pharmaceutical preparations and concentration-time profiles in urine.

Determination of Norfloxacin and Enrofloxacin by Solid-Phase Microextraction/High-Performance Liquid Chromatography

A solid-phase microextraction (SPME) method followed by separation with high-performance liquid chromatography and subsequent UV detection was developed for the determination of norfloxacin and enrofloxacin. The simple and sensitive preconcentration technique uses 280 nm wavelength in mobile phase of citrate buffer (0.01 M), pH 3.8, prepared in water (A) and acetonitrile (B), with composition of the mobile phase A:B, 40:60, at a flow rate of 1.0 mL/min. A C18 reversed-phase analytical column (5 microm) was selected as separation medium for the technique. To obtain optimum extraction efficiency, several parameters relating to SPME were investigated. The method was linear over the range of 10-100 ng/mL for norfloxacin and enrofloxacin with a correlation coefficient (R2) value of 0.9972 and 0.9980 for norfloxacin and enrofloxacin, respectively. Using the SPME method, the detection limits (signal-to-noise ratio = 3) are 0.17 and 0.12 ng/mL for norfloxacin and enrofloxacin, respectively.

Determination of levofloxacin and norfloxacin by capillary electrophoresis with electrochemiluminescence detection and applications in human urine

A novel method for the determination of norfloxacin (NOR) and levofloxacin (LVX) was developed by CE separation and electrochemiluminesence detection (ECL). The methods for capillary conditioning and the effect of solvent type were studied. Parameters affecting the CE and ECL were also investigated. Under the optimum conditions, the two analytes were well separated within 9 min. The LODs (S/N = 3) in standard solution are 4.8 x 10(-7) mol/L for NOR and 6.4 x 10(-7) mol/L for LVX, respectively. The precisions of intraday and interday are less than 4.2 and 8.1%, respectively. The LOQs (S/N = 10) in real human urine samples are 1.2 x 10(-6) mol/L for NOR and 1.4 x 10(-6) mol/L for LVX, respectively. The applicability of the proposed method was illustrated in the determination of NOR and LVX in human urine samples and the monitoring of pharmacokinetics for NOR. The recoveries of NOR and LVX at different levels in human urine samples were between 84.3 and 92.3%.

Simultaneous kinetic spectrophotometric determination of norfloxacin and rifampicin in pharmaceutical formulation and human urine samples by use of chemometrics approaches

A kinetic spectrophotometric method with aid of chemometrics is proposed for the simultaneous determination of norfloxacin and rifampicin in mixtures. The proposed method was applied for the simultaneous determination of these two compounds in pharmaceutical formulation and human urine samples, and the results obtained are similar to those obtained by high performance liquid chromatography.

Capillary electrophoresis with electrochemiluminescence detection for the analysis of quinolone drugs and pharmacokinetics study

A novel method for the determination of two quinolone drugs norfloxacin (NOR) and levofloxacin (LVX) was described by capillary electrophoresis with electrochemiluminescence detection. The good relationship ( r ≥ 0.9991) between peak area and concentration of analytes was established over two orders of magnitude. The limits of detection (LOD, S/N = 3) in standard solution are 4.8 × 10 −7 mol/L for NOR and 6.4 × 10 −7 mol/L for LVX, respectively. The limits of quantitation (LOQ, S/N = 10) in real human urine samples are 1.2 × 10 −6 mol/L for NOR and 1.4 × 10 −6 mol/L for LVX, respectively. The present method was successfully applied to the determination of NOR and LVX in human urine and the study of pharmacokinetics of NOR.

Validation of a Reversed-Phase High-Performance Liquid Chromatography Method With Fluorescence Detection for the Bioequivalence Study of Norfloxacin in Plasma Samples

A robust method for the determination of norfloxacin in human plasma, using reversed-phase high-performance liquid chromatography (RP-HPLC) with fluorescence detection, has been developed. The method involves precipitation of plasma protein with acetonitrile and the use of ciprofloxacin as internal standard (IS). Chromatographic separations were performed on a Synergi MAX-RP 150 x 4.6-mm, 4-micro column with an elution system consisting of a mixture of phosphate buffer-acetonitrile (85:15, v/v). The calibration curve was linear, in the range of 30 to 3500 ng/mL. The recoveries at concentrations of 90, 1400, and 2800 ng/mL were 103.5%, 100.2%, and 100.2%, respectively. The quantification limit for norfloxacin was 30 ng/mL per 10-microL injection employing fluorescence detection with excitation and emission set at 300 and 450 nm, respectively. The method validation included examining the within-run and between-run precision and accuracy and ensuring that these were within accepted limits; in summary, the precision was <8.6% and accuracy ranged from 95.8% to 104.1% for concentration from 90 to 2800 ng/mL. The precision and accuracy for the lowest calibration standard (30 ng/mL) was well within accepted limits for lower limit of quantification. The method was then applied in a bioequivalence study in healthy volunteers given 400-mg doses of reference and test formulations of norfloxacin in random order and including a 7-day washout phase.

Column High-Performance Liquid Chromatographic Determination of Norfloxacin and Its Main Impurities in Pharmaceuticals

A gradient reversed-phase column high-performance liquid chromatographic method was developed for the detection and quantification of norfloxacin and its major impurities in norfloxacin-containing pharmaceuticals. Chromatographic separations were performed under the following experimental conditions: column, Zorbax SB RP-18 (5 microm, 250 x 4.6 mm); injection volume, 20 microL; mobile phase, 0.05 M NaH2PO4 (pH 2.5)-acetonitrile (87 + 13) for 16 min and (58 + 42) for 9 min (stepwise gradient); and flow rate, 1.3 mL/min. All analyses were performed at 25 degrees C, and the eluate was monitored at 275 nm using a diode array detector. Linearity (correlation coefficient = 0.999), recovery (99.3-101.8%), relative standard deviation (0.2-0.7%), and quantitation limit (0.12-0.47 microg/mL) were evaluated and found to be satisfactory. The method is simple, rapid, and convenient for purity control of norfloxacin in both raw materials and dosage forms.

Determination of norfloxacin in pharmaceuticals, human serum, and urine using a luminol—dissolved oxygen chemiluminescence system

AbstractA sensitive chemiluminescence method, based on the enhancive effect of norfloxacin on the reaction between luminol and dissolved oxygen in a flow injection system, was proposed for the determination of norfloxacin. The increment of the chemiluminiscence intensity was proportional to the concentration of norfloxacin, giving a calibration graph linear over the concentration from 0.4 ng mL−1 to 400.0 ng mL−1 (r 2 = 0.9988) with the detection limit of 0.1 ng mL−1 (3 × σ noise). At the flow rate of 2.0 mL min−1, a complete determination of norfloxacin, including sampling and washing, could be accomplished in 30 s with the relative standard deviation lower than 3.0 %. The proposed method was applied successfully to determine norfloxacin in pharmaceuticals, human urine, and serum. Possible mechanism of the reaction was also discussed.

Molecular Imprinting-Chemiluminescence Determination of Norfloxacin Using a Norfloxacin-Imprinted Polymer as the Recognition Material

A selective molecular imprinting-chemiluminescence method was developed for the determination of norfloxacin by using a norfloxacin-imprinted polymer as recognition material and the Ce(IV)-sodium sulfite-norfloxacin chemiluminescence reaction as the detection system. The chemiluminescence intensity responded linearly to the concentration of norfloxacin within 1.0×10−7∼1.0×10−5 mol L−1 with a detection limit of 3×10−8 mol L−1. The relative standard deviation for 5.0×10−7 mol L−1 norfloxacin solution was 2.4% (n = 7). This method was applied to the determination of norfloxacin in urine samples, and the results obtained were satisfactory.

Molecular Charge Transfer Complexes of Norfloxacin with Nitrobenzenes

Abstract Charge Transfer molecular complexes of Norfloxacin-[1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl) 3-quinolone carboxylic acid] with m-dinitrobenzene, picric acid, 3,5-dinitrobenzoic acid and 3,5-dinitrosalicylic acid have been synthesized and characterized by elemental analysis as well as different spectroscopic techniques. Spectral characteristics and stability of the complexes are investigated and discussed in terms of donor molecular structure, π-acceptor electron affinity, and solvent polarity. It is deduced that the complexes are mainly of the n–π* and π–π* types. Ionization potential of the donor was estimated from the CT transition energies of their complexes. The potentiality of the electron acceptors as new chromophoric reagents for the spectrophotometric determination of Norfloxacin was studied by extensive investigation of optimum conditions favouring the formation of the colored complexes.