RESUMO
In this report, we synthesized MgCr(2)O(4) nanoparticles and then multiwall carbon nanotubes were decorated with the MgCr(2)O(4) nanoparticles. The characteristics of the new materials were studied with different techniques such as transmission electron microscopy, Fourier transform infrared spectroscopy, atomic force microscopy and electrochemical impedance spectroscopy. The multiwall carbon nanotubes decorated with MgCr(2)O(4) nanoparticles were used as a new mediator for voltammetric determination of azithromycin. The oxidation peak of azithromycin was appeared at a potential of about 720 mV at a surface of the modified electrode. Differential pulse voltammetry exhibited two wide linear dynamic ranges of 0.25-4.0 and 4.0-10.0 µmol L(-1) azithromycin with a detection limit of 0.07 µmol L(-1) at pH 7.0. The influence of potential interfering compounds on the selectivity was studied. Finally, the modified electrode showed good sensitivity, selectivity and stability for the determination of azithromycin in real samples.
Assuntos
Azitromicina/sangue , Azitromicina/urina , Técnicas Biossensoriais/instrumentação , Compostos de Cromo/química , Técnicas Eletroquímicas/instrumentação , Nanotubos de Carbono/química , Óxidos/química , Calibragem , Espectroscopia Dielétrica , Estabilidade de Medicamentos , Eletricidade , Eletrodos , Vidro/química , Humanos , Concentração de Íons de Hidrogênio , Limite de Detecção , Fenômenos Magnéticos , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios XRESUMO
A sensitive method for simultaneous determination of azithromycin (AZI), acetylspiramycin (ACE), erythromycin (ERY), and josamycin (JOS) was developed by CE coupled with electrochemiluminescence detection with Ru(bpy)(3) (2+). The parameters related to separation and detection were investigated in detail. The four macrolides were well separated and detected within 6 min under the optimized conditions. The LOD (S/N=3) of AZI, ACE, ERY, and JOS were 1.2 x 10(-9), 7.1 x 10(-9), 3.9 x 10(-8) and 9.5 x 10(-8) mol/L, respectively. The LOQ (S/N=10) of AZI, ACE, ERY, and JOS in human urine were 8.2 x 10(-8), 2.5 x 10(-7), 8.9 x 10(-7) and 1.2 x 10(-6) mol/L, respectively. The recoveries of the four macrolides in human urine and pharmaceutical tablet samples were 85.0-104.0% at different concentration levels.
Assuntos
Eletroforese Capilar/métodos , Medições Luminescentes/métodos , Macrolídeos/análise , 2,2'-Dipiridil/análogos & derivados , 2,2'-Dipiridil/química , Azitromicina/análise , Azitromicina/urina , Humanos , Concentração de Íons de Hidrogênio , Macrolídeos/urina , Compostos Organometálicos/química , Sensibilidade e Especificidade , Comprimidos/químicaRESUMO
A simple flow injection chemiluminescence method with synergistic enhancement has been investigated for the rapid and sensitive determination of azithromycin. The synergistic action was significant in the chemiluminescence system of luminol-hydrogen peroxide with azithromycin as an enhancer. The enhanced chemiluminescence intensity was linear with the concentration of azithromycin over the range from 0.1 pg x mL(-1) to 1.0 ng x mL(-1) (r(2=)0.9988) with a detection limit (3sigma) of 0.04 pg x mL(-1). At a flow rate of 2.0 mL x min(-1), a complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard deviation of less than 3.0%. The proposed method was applied successfully in the assay of azithromycin in pharmaceutical preparations, human urine and serum without any pre-treatment procedure.
Assuntos
Antibacterianos/análise , Azitromicina/análise , Análise de Injeção de Fluxo/métodos , Peróxido de Hidrogênio/química , Luminol/química , Antibacterianos/química , Antibacterianos/urina , Azitromicina/química , Azitromicina/urina , Humanos , Cinética , Medições Luminescentes , Estrutura Molecular , Sensibilidade e Especificidade , Hidróxido de Sódio/químicaRESUMO
One hundred ninety-two female patients with acute urethral syndrome caused by Ureaplasma urealyticum were examined. First, patients were divided into two groups: those with clinical symptoms present for less than 3 weeks before the start of treatment and those with clinical symptoms 3 weeks or longer before the beginning of therapy. The patients were then further divided into groups and randomized to receive azithromycin once daily in a single dose of 1 g or 500 mg once daily for 6 days, or to receive doxycycline 100 mg b.i.d. for 14 days or 100 mg b.i.d. for 7 days (eight study groups in all). Clinical and bacteriological efficacy were evaluated 3 weeks after the end of therapy. In the group of patients with disease symptoms lasting for 3 weeks or longer, eradication and clinical cure rates were significantly higher after the administration of azithromycin at a dose of 1 x 500 mg/6 days than after a single dose of 1 g (p < 0.001).
