Stability-indicating methods for the spectrophotometric determination of norfloxacin

Khateeb, Sonia Z. El; Razek, Sawsan A. Abdel; Amer, M. M.

doi:10.1016/s0731-7085(97)00271-9

Cited by 27 publications

(9 citation statements)

References 8 publications

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“…22) They were expected to decompose into their decarboxylated degradates when heated with 2 M HCl while protected from light. 23) In the present work the studied drugs were determined in the presence of their decarboxylated degradates since the carboxylic acid group is required for the pharmacological activity. 22,23) Densitometric Method Shah et al 10) determined Lfx in urine using HPTLC plates and butanol/methanol/ethyl acetate/6 M ammonia (4/2/3/2, v/v/v/v) and scanning at 292 nm.…”

Section: Resultsmentioning

confidence: 99%

“…23) In the present work the studied drugs were determined in the presence of their decarboxylated degradates since the carboxylic acid group is required for the pharmacological activity. 22,23) Densitometric Method Shah et al 10) determined Lfx in urine using HPTLC plates and butanol/methanol/ethyl acetate/6 M ammonia (4/2/3/2, v/v/v/v) and scanning at 292 nm. Meanwhile, Zheng and Feng 12) determined Sfx using 0.27 M EDTA-treated silica gel plates and ethanol/ethyl acetate/ dichloroethane/10% ammonia (4/3/2/1, v/v/v/v) as developing solvent.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore the detection of the decarboxylated degradates is of particular importance since the carboxylic acid group is required for their pharmacological activity. 22,23) Thus the aim of this work is to develop efficient, simple TLC densitometric and derivative spectrophotometric methods for the selective determination of Lfx, Mfx, and Sfx in their pure form or in pharmaceutical dosage forms without interference from their decarboxylated degradates. …”

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Stability Indicating Methods for the Determination of Some Fluoroquinolones in the Presence of Their Decarboxylated Degradates

Salem

El-Guindi

Mikael

et al. 2006

CHEMICAL & PHARMACEUTICAL BULLETIN

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Lomefloxacin hydrochloride (Lfx), moxifloxacin hydrochloride (Mfx), and sparfloxacin (Sfx) are 4-fluoroquinolone carboxylic acid antibacterials having the following structures.The 4-quinolone antibacterials are a group of synthetic antibacterials structurally related to nalidixic acid. 1) They act through the inhibition of DNA gyrase (in GϪve bacteria) or topisomerase (in Gϩve bacteria).2) Several methods have been reported for their analysis including UV-visible spectrophotometry, 3,4) spectrofluorometry, 5-7) atomic absorption spectrophotometry, 8) chromatography, [9][10][11][12][13] electrophoresis, [14][15][16] flow injection analysis, 17,18) and electrochemical methods. [19][20][21] Structure activity studies have shown that the 1,4-dihydro-4-oxo-3-pyridine carboxylic acid moiety is essential for antibacterial activity of the fluoroquinolones. Therefore the detection of the decarboxylated degradates is of particular importance since the carboxylic acid group is required for their pharmacological activity. 22,23) Thus the aim of this work is to develop efficient, simple TLC densitometric and derivative spectrophotometric methods for the selective determination of Lfx, Mfx, and Sfx in their pure form or in pharmaceutical dosage forms without interference from their decarboxylated degradates. ExperimentalApparatus Labomed Spectro UV-Vis Double Beam PC 8 scanning auto cells spectrophotometer, with matched 10 mm path-length quartz cells. The derivative conditions were delta lambda of 5 nm and scaling factorϭ10.Shimadzu dual wavelength flying spots CS9301 densitometer. The experimental conditions of the measurement were as follow: wavelengthϭ288, 290, and 292 nm for Lfx, Mfx, and Sfx, respectively; photomodeϭreflection; scan modeϭzigzag, and swing widthϭ16.UV lamp, short and long wavelength 254 and 365 nm, spectroline (U.S.A.).Glass jar for TLC with lid 22ϫ25ϫ10 cm. TLC plates 20ϫ20 cm, 0.25 mm thickness silica gel 60 GF254 (E. Merck).HPTLC plates 20ϫ20 cm, silica gel nanoplates F254, sprayed with 1% EDTA solution in 5% dipotassium hydrogen phosphate then heated for 1 h at 120°C (E. Merck).10 ml Hamilton microsyringe. Bruker IR spectrophotometer. Two stability-indicating methods, namely densitometric TLC and derivative spectrophotometry for the determination of the fluoroquinolone antibacterials lomefloxacin (Lfx), moxifloxacin (Mfx), and sparfloxacin (Sfx) in the presence of their acid degradates are described. Acid degradation was adopted and the main decarboxylated product separated by TLC. Degradation products were identified confirming a previously mentioned degradation scheme. The densitometric method is based on the separation of the intact drug from its acid degradation product on silica gel G plates using different mobile phases and the spots of the intact drugs were scanned at 288, 290, and 292 nm for Lfx, Mfx, and Sfx, respectively. The derivative spectrophotometric method utilizes first derivative D 1 UV spectrophotometry with zero crossing points at 295. Materials and Reagents

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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Stability Indicating Methods for the Determination of Some Fluoroquinolones in the Presence of Their Decarboxylated Degradates

Salem

El-Guindi

Mikael

et al. 2006

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…Among them, spectrophotometry, flurimetry, and luminescence attracted wide attention due to the cheap equipment and simple process. They are based on the reactions of hyperchromicity [17][18][19][20][21][22][23] , fluorescence [24][25][26][27][28] , and luminescence [9,11,[29][30][31][32][33][34][35] between fluoroquinolones and Fe (III), Fe (II), Al (III), Tb (III), Eu (III), Sc (III), Zn (II), W (VI), V (V), and Ce (IV). Furthermore, formed chelations of fluoroquinolone are the important factors in the antibacterial activity and bioavailability [36] .…”

Section: Introductionmentioning

confidence: 99%

Study on the absorption and fluorescence and resonance Rayleigh scattering spectra of Cu (II)-fluoroquinolone chelates with erythrosine and their applications

Wang

Liu

et al. 2008

Sci. China Ser. B-Chem.

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In pH 4.2-5.0 Britton-Robinson buffer solution medium, fluoroquinolone antibiotics (FLQs), such as ciprofloxacin (CIP), norfloxacin (NOR), ofloxacin (OF), levofloxacin (LEV), lomefloxacin (LOM), and sparfloxacin (SPA), react with Cu (II) to form chelate cations, which further bind with erythrosine to form the ion association complexes. They can result in the changes of the absorption spectra. Simultaneously, erythrosine fades obviously and the maximum fading wavelength is located at 526 nm. The fading reactions have high sensitivities. Thus, new spectrophotometries of determination for these drugs are developed. The ion-association reactions result in the quenching of fluorescence, which also have high sensitivities. The detection limits for six antibiotics are in the range of 7.1-12.2 μg·L −1 . Furthermore, the reactions can result in the enhancement of resonance Rayleigh scattering (RRS). The maximum scattering peaks of six ion-association complexes are located at 566 nm, and there are two small RRS peaks at 333 nm and 287 nm. The detection limits for fluoroquinolone antibiotics are in the range of 1.70-3.10 μg·L −1 for RRS method. Among the above three methods, the RRS method has the highest sensitivity. In this work, we investigated the spectral characteristics of the absorption, fluorescence and RRS, the optimum conditions of the reactions, and the properties of the analytical chemistry. In addition, the mechanism of reactions were discussed by density function theory (DFT) and AM1 methods.

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“…1,2) Methods were reported for its determination as titrimetric, 3) LC, [4][5][6][7][8][9][10] LC-MS, [11][12][13] spectrometric, [14][15][16] spectrofluorimetric [17][18][19][20] and electrochemical. 21) Tinidazole (Tnd), 1-[2-(ethyl sulfonyl)ethyl]-2-methyl-5-nitro-1H-imidazole is an antiprotozoal, antiamaebic and antibacterial drug.…”

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confidence: 99%

Stability Indicating Methods for the Determination of Norfloxacin in Mixture with Tinidazole

Mohammad

Zawilla

El-Anwar

et al. 2007

CHEMICAL & PHARMACEUTICAL BULLETIN

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Stability-indicating methods for the spectrophotometric determination of norfloxacin

Cited by 27 publications

References 8 publications

Stability Indicating Methods for the Determination of Some Fluoroquinolones in the Presence of Their Decarboxylated Degradates

Stability Indicating Methods for the Determination of Some Fluoroquinolones in the Presence of Their Decarboxylated Degradates

Study on the absorption and fluorescence and resonance Rayleigh scattering spectra of Cu (II)-fluoroquinolone chelates with erythrosine and their applications

Stability Indicating Methods for the Determination of Norfloxacin in Mixture with Tinidazole

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