• Bulletin of the Korean Chemical Society
• /
• v.29 no.5
• /
• pp.988-992
• /
• 2008

A poly(methyl red) film-modified glassy carbon electrode (PMRE) was fabricated for determination of norfloxacin (NFX). The electrochemical behavior of NFX was investigated and a well-defined oxidation peak with high sensitivity was observed at the film electrode. PMRE greatly enhanced the oxidation peak current of NFX owing to the extraordinary properties of poly(methyl red) film. Based on this, a sensitive and simple voltammetric method was developed for measurement of NFX. A sensitive linear voltammetric response for NFX was obtained in the concentration range of $1\;{\times}\;10^{-6}\;-\;1\;{\times}\;10^{-4}$ mol/L and the detection limit was $1\;{\times}\;10^{-7}$ mol/L using linear sweep voltammetry (LSV). The proposed method possessed advantages such as low detection limit, fast response, low cost and simplicity. The practical application of this new analytical method was demonstrated with NFX pharmaceuticals.

• Korean Journal of Veterinary Research
• /
• v.37 no.1
• /
• pp.147-154
• /
• 1997

국내에서 많이 사용되고 있는 제2세대 quinolone 항생제인 norfloxacin(NFX)에 대한 약역학적인 특성을 구명하기 위하여 국내에서 분리된 동물유래 병원성 세균에 대하여 시험관내에서 실험을 수행하여 다음과 같은 결과를 얻었다. 즉, E coli(n=89) 대한 NFX의 $MIC_{50}$와 $MIC_{90}$는 공히 0.02g/ml이었으며, Streptococcus spp.(n=36)에 대한 NFX의 $MIC_{50}$는 2g/ml 그리고 $MIC_{90}$는 4g/ml로 나타났다. Salmonella spp.(n=56)에 대한 NFX의 $MIC_{50}$와 $MIC_{90}$ 모두 0.2g/ml로 강한 항균력을 보였으며, Streptococcus spp.(n=24)에 대한 NFX의 $MIC_{50}$는 2g/ml 그리고 $MIC_{90}$가 4g/ml로 나타났다. Bacillus spp.(n=34)는 NFX의 $MIC_{50}$와 $MIC_{90}$는 모두 0.4g/ml으로서 대부분의 병원성 세균에 대해서 $MIC_{50}$와 $MIC_{90}$치가 동일하든지 또는 매우 비슷한 수치를 보여주었다. 그러나 NFX는 혐기성세균인 Clostridium spp.(n=34)에 대해서는 항균력이 매우 낮았다. 현재 수의임상에서 항균제 병용요법이 많이 응용되고 있는 것을 고려하여 NFX와 다른 항생물질간의 분획억제농도 (FICs)를 E coli 88ac을 시험균주로 하여 실험한 결과, NFX와 colistin과 병용할 때 FIC 값이 0.38로서 상승작용을 그리고 gentamicin, trimethoprim, amikacin, penicillin 및 tylosin과의 병용시 FIC 값이 각각 0.52, 0.56, 0.63, 1.00 및 1.02로서 상가작용을 보여주었으며, tetracyclin과의 병용시의 FIC값은 1.49로서 길항작용을 나타냄을 알 수 있었다. 한편 실제 항균제의 임상적용시 매우 주요한 요소인 항균활성후 저농도유효성(PAE)을 알아보기 위하여 E coli AB1157을 시험균주로 측정한 결과 PAE은 0.90~1.02 시간 그리고 S aureus R-209에 대해서는 PAE가 1.58~1.99 시간으로서 그람음성균 및 그람양성균 모두에 대해서 긴 PAE를 갖고 있음을 알 수 있었다.

• Korean Journal of Veterinary Research
• /
• v.44 no.2
• /
• pp.201-206
• /
• 2004

Norfloxacin (NFX) is a fluorquinolone antibacterial agent with a high antimicrobial activity and might have great potential for treating common infections in poultry. The objective of this study was to obtain comparative pharmacokinetic data after a single oral administration and medication with drinking water of norfloxacin-glycine acetate (NFX-GA) at the dose rate of 10 mg/kg bw in broilers. Fifty minutes following oral administration of NFX-GA, serum concentrations peaked at $1.32{\mu}g/mL$ (range $1.03-1.45{\mu}g/mL$). Serum concentration of NFX declined with a half-life of $7.21{\pm}1.81$ h. On the third day after administration of medicated drinking water, steady-state was reached, with mean concentrations of NFX of $0.70{\pm}0.35{\mu}g/mL$. The concentration of NFX after medication of NFX-GA with drinking for 3 days provides sufficient levels to obtain maximum therapeutic effects and maintains the serum persistence of concentration exceeding MIC.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.6C
• /
• pp.343-348
• /
• 2011

This paper introduces a design for real time wireless headset using ANC (active noise control) system based on NFxLMS adaptive filter algorithm. The training time of the proposed system is significantly reduced by using the RMS delay spread of a channel as an error correction parameter, and convergence rate of the FxLMS filter has been improved with updating the coefficients of the NFxLMS filter, which we have got during the training process. Our system has shorter training time and better convergence rate at the same noise reduction level than the conventional system under real noisy environment.

• Journal of Drive and Control
• /
• v.9 no.1
• /
• pp.44-51
• /
• 2012

• Polymer(Korea)
• /
• v.33 no.2
• /
• pp.137-143
• /
• 2009

We prepared norfloxacin (NFX)-incorporated polymeric micelle using poly ($\varepsilon$-caprolactone)/poly(ethylene glycol) (PCL/PEG, CE) diblock copolymers. Particle size was from 60 to 200 nm according to the PCL block length. Their critical association concentration (CAC) was decreased according to the increase of PCL block length. $^1H$-NMR study showed core-shell type micelle structures of CE diblock copolymers in the aqueous environment. Drug release from polymeric micelle was continued over 2 days. Duration of drug release was varied according to the PCL block length and drug contents. At antimicrobial activity test, polymeric micelle showed almost similar cytotoxicity compared to NFX itself.

• Journal of fish pathology
• /
• v.15 no.2
• /
• pp.49-56
• /
• 2002

Effects of Temperature on the Pharmacokinetics of norfloxecin (NFX) were studied in the cultured carp,Cyprinus carpio, and cel, Anguilla japonica, using high performance liquid chromatography (HPLC) originally developed for quinolone determination in livesrocks. Pharmacokinetics of NFX was apparently affected by ambiem water temperature. In a two-compaament model for carp after oral dosage of 20 mg/K01 at $13^{\circ}C$ and $23^{\circ}C$ and 5.20/hr, respectively. In carp the $K_{\iota\nu}$, $T_{max}$and $C_{max}$ for carp at $13^{\circ}C$ were 13.30/hr, 17.44 ${\mu}g$/$m\ell$ and 7.00 ${\mu}g$/$m\ell$, respectively. The" correspoeding values at $23^{\circ}C$ were 3.93/hr, 15.40 ${\mu}g$/$m\ell$ and 9.44 ${\mu}g$/$m\ell$, respectively. The AUC and T were 355.66 ${\mu}g$ hr/$m\ell$, and 12.70 hr at $13^{\circ}C$ and 417,24 ${\mu}g$ hr/$m\ell$ and 13.86 hrs at $23^{\circ}C$, respectively. Similar trends were revealed in the NFX pharmacokinetics of eel kept under the two water temperature regimes aftee oral NFX dosage of 20 mg/kg. These pharmacokinetkal results have some implication in the optimal usage of recently introduced antibacterials in farmed fish, which were originally adapted for poultry and mammalian species.

• Polymer(Korea)
• /
• v.26 no.4
• /
• pp.535-542
• /
• 2002

We have prepared the surfactant-free nanoparticles of poly(DL-lactide-co-glycolide) (PLGA) by dialysis method and their physicochemical properties such as particle size and drug contents were investigated against various solvent. The size of PLGA nanoparticles prepared by using dimethylacetamide (DMAc), dimethylformamide (DMF), and dimethylsulfoxide (DMSO) was smaller than that from acetone. Also, the order of drug contents was DMAc>DMF>DMSO=acetone. These phenomena could be expected from the fact that solvent affects the size of nanoparticles and drug contents. The PLGA nanoparticles have a good spherical shapes as observed from scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Also, surfactant-free nanoparticles entrapping norfloxacin (NFx) have a good drug loading capacity without free-drug on the surface of nanoparticles confirmed by the analysis of X-ray powder diffraction. Release kinetics of NFx used as a model drug was governed not only by drug contents but also by particle size. Also, the biodegradation rate of PLGA nanoparticles prepared from DMF was faster than that prepared from acetone, indicating that the biodegradation of PLGA nanoparticles is size-dependent.

• Bulletin of the Korean Chemical Society
• /
• v.19 no.9
• /
• pp.962-967
• /
• 1998

Block copolymers consisting of poly(rbenzyl L-glutamate) (PBLG) as the hydrophobic part and poly(ethylene oxide) (PEO) as the hydrophilic part were synthesized and characterized. Polymeric micelles of the block copolymers (abbreviated GEG) were prepared by a dialysis method. The GEG block copolymers were associated in water to form polymeric micelles, and the critical micelle concentration (CMC) values of the block copolymers decreased with increasing PBLG chain length in the block copolymers. Transmission electron microscopy (TEM) observations revealed polymeric micelles of spherical shapes. From dynamic light scattering (DLS) study, sizes of polymeric micelles of GEG-1, GEG-2, and GEG-3 copolymer were 106.5±59.2 nm, 79.4±46.0 nm, and 37.9±13.3 nm, respectively. The drug loading contents of GEG-1, GEG-2 and GEG-3 polymeric micelles were 12.6, 11.9, and 11.0 wt %, respectively. These results indicated that the drugloading contents were dependent on PBLG chain length in the copolymer; the longer the PBLG chain length, the more the drug-loading contents. Release of norfloxacin (NFX) from the nanoparticles was slower in higher loading contents of NFX than in lower loading contents due to the hydrophobic interaction between PBLG core and NFX.

• Korean Journal of Veterinary Service
• /
• v.29 no.2
• /
• pp.111-122
• /
• 2006

A direct, accurate and sensitive chromatographic analytical method for quantitative determination of four fluoroquinolones (norfloxacin, cirprofloxacin, danofloxacin and enrofloxacin) in chicken, pork and beef edible muscle is proposed in the present study. The developed method was successfully applied to the determination of enrofloxacin, as the main component of commercially available veterinary drugs. The samples were homogenized and the antimicrobials were added, then they were extracted twice with dichloromethane. Fluoroquinolone antibiotics were separated on an agilent $250x4mm,\;C_{18},\;5{\mu}m$, analytical column, at $25^{\circ}C$. The mobile phase consisted of a mixture of DW : acetonitrile : triethylamine(80:19:1%, v/v, pH 3.0) leading to retention times less than 14 min. at a flow rate 0.5 ml/min. These fluoroquinolones were detected by liquid chromatography with fluorescence at 290 nm excitation and 465 nm emission. The limits of quantification in each edible muscle (chicken, pork, and beef) were 0.32-6.54 ng/g. Using 0.5 g of each sample, average recovery rates at fortification levels of 0.05, 0.1 and 0.2 ${\mu}g/ml$ ranged 70.14-71.71% for NFX, 71.87-73.89% for CFX, 82.16-92.35% for DFX, and 90.13-98.12 for EFX This is a simple and economic method to quantify the presence of NFX, CFX, EFX and DFX in edible muscle of animal origin.