Stability indicating square-wave stripping voltammetric method for determination of gatifloxacin in pharmaceutical formulation and human blood

Abstract

Um método de voltametria de re-dissolução catódica adsortiva de onda quadrada, indicativa de estabilidade, completamente validado, sensível e preciso foi desenvolvido para determinação de gatifloxacina na forma bruta, em formulações farmacêuticas e em amostras de plasma e soro humano. Os limites de detecção encontrados de gatifloxacina na forma bruta e no soro humano foram 1,5 × 10 -9 e 2,2 × 10 -9 mol L -1 , respectivamente. O método descrito foi aplicado com sucesso na determinação de gatifloxacina em formulações farmacêuticas e em amostras biológicas humanas sem extração prévia às análises. Interferências de excipientes comuns, de alguns íons de metais comuns, de espécies orgânicas, de fármacos co-administrados e de produtos de degradação induzida por ácido não foram significativos, durante a análise de gatifloxacina nas diversas amostras analisadas. Além disso, parâmetros farmacocinéticos de gatifloxacina em plasma de voluntários saudáveis, após a administração de uma dose oral (400 mg de gatifloxacina) foram também estimados por meio do método voltamétrico de re-dissolução descrito.A fully validated, sensitive and precise stability-indicating square-wave adsorptive cathodic stripping voltammetric method has been developed for determination of gatifloxacin in the bulk form, pharmaceutical formulation, and in spiked human serum and real plasma samples. The achieved detection limits of gatifloxacin in the bulk form and human serum were 1.5 × 10 -9 and 2.2 × 10 -9 mol L -1 , respectively. The described method was applied successfully for determination of gatifloxacin in formulation and human biological samples without extraction prior to the analysis. No significant interferences from common excipients, some common metal ions, organic species, co-administrated drugs and from the acid-induced degradation products were obtained during analysis of gatifloxacin in the various analyzed samples. Besides, pharmacokinetic parameters of gatifloxacin in plasma of healthy volunteers following the administration of an oral single dose (400 mg gatifloxacin) were also estimated by means of the described stripping voltammetric method.Keywords: gatifloxacin, tequin tablets, human blood, stripping voltammetry, pharmacokinetic parameters IntroductionGatifloxacin (1-cyclopropyl-6-fluoro-1, 4-dihydro-8-methoxy-7-[3-methyl-1-piperazinyl]-4-oxo-3-quinoline carboxylic acid), (Scheme 1), is a synthetic broad-spectrum antimicrobial fluoroquinolone. It is active against both gram-negative and gram-positive bacteria and used in the treatment of a wide range of infections. 1,2 Its absolute bioavailability is 96%, with mean peak plasma concentration of 3.1 to 3.6 µg mL -1 usually occurring within 1.0 to 2.0 h after administration of an oral single dosing of a 400 mg gatifloxacin. [2][3][4] It undergoes limited biotransformation in humans with less than 1% of the dose excreted in the urine as ethylenediamine and methylethylenediamine metabolites. 2 Various instrumental analytical methods have been described for assay of gatifloxacin in b...

Electrochemical determination of gatifloxacin, moxifloxacin and sparfloxacin fluoroquinolonic antibiotics on glassy carbon electrode in pharmaceutical formulations

“…The strong tendency of fluoroquinolones to accumulate at the electrode surface offers a possibility of their highly sensitive determination by stripping voltammetry. Stripping voltammetry techniques have been used for determination of several fluoroquinolones, such as norfloxacin,14, 15 fleroxacin,16 pefloxacin,17, 18 lomefloxacin,19 trovafloxacin,20 ofloxacin,21, 22 enrofloxacin,23 levofloxacin,24, 25 gatifloxacin,26 danofloxacin, and orbifloxacin27 with sensitivity equivalent to that of HPLC techniques.…”