Rapid titrimetric and spectrophotometric determination of ofloxacin in pharmaceuticals using N-bromosuccinimide / Determinação titulométrico e espectrofotométrico rápido de ofloxacina em produtos farmacêuticos usando N -bromosuccinimida

One titrimetric and two spectrophotometric methods have been described for the determination of ofloxacin (OFX) in bulk drug and in tablets, employing N-Bromosuccinimide as an analytical reagent. The proposed methods involve the addition of a known excess of NBS to OFX in acid medium, followed by determination of unreacted NBS. In titrimetry, the unreacted NBS is determined iodometrically, and in spectrophotometry, unreacted NBS is determined by reacting with a fixed amount of either indigo carmine (Method A) or metanil yellow (Method B). In all the methods, the amount of NBS reacted corresponds to the amount of OFX. Titrimetry allows the determination of 1-8 mg of OFX and the calculations are based on a 1:5 (OFX:NBS) reaction stoichiometry. In spectrophotometry, Beer's law is obeyed in the concentration ranges 0.5-5.0 µg/mL for method A and 0.3-3.0 µg/mL for method B. The molar absorptivities are calculated to be 5.53x10(4) and 9.24x10(4) L/mol/cm for method A and method B, respectively. The methods developed were applied to the assay of OFX in tablets, and results compared statistically with those of a reference method. The accuracy and reliability of the methods were further ascertained by performing recovery tests via the standard-addition method.

Descrevem-se métodos, um titulométrico e dois espectrofotométricos, para a determinação de ofloxacino (OFX) na matéria-prima e em comprimidos, empregando a N-bromossuccinimida (NBS) como reagente analítico. Os métodos propostos envolvem a adição de excesso conhecido de NBS ao OFX, em meio ácido, seguida de determinação do NBS que não reagiu. Na titulometria, o NBS que não reagiu é determinado iodometricamente e na espectrofotometria, o NBS que não reagiu é determinado pela reação com quantidade fixa de índigo carmim (Método A) ou amarelo de metanila (Método B). Em todos os métodos, a quantidade de NBS que reagiu corresponde à quantidade de OFX. A titulometria permite a determinação de 1-8 mg de OFX e os cálculos se baseiam na estequiometria de reação de 1:5 (OFX:NBS). Na espectrofotometria, a Lei de Beer é obedecida nas faixas de concentração de 0,5-5,0 µg/mL, para o método A, e de 0,3-3,0 µg/mL, para o método B, respectivamente. Os métodos desenvolvidos foram aplicados para o teste de OFX em comprimidos e os resultados foram comparados estatisticamente com aqueles do método de referência. A precisão e a confiabilidade dos métodos foram, posteriormente, verificadas por meio dos testes de recuperação via método de adição de padrão.

Kinetics of oxidation of [N-isopropylidene - hydrazine-s-methyldithiocarboxylate] cobalt [II] complex by N-bromosuccinimide and N-bromophthalimide in non polar solvent

The kinetics of oxidation of [N-isopropylidene - hydrazine-s-methyldithio-carboxylate] cobalt [II] complex by N-bromosuccinimide [NBS] and N-bromophthalimide [NBP] in benzene solvent were studied spectrophotometrically at lambda = 300 - 310 nm and at 281-297 K for a range of complex and oxidant concentrations. The reaction exhibited a first order dependence on both reactants. The detection of the initial cobalt [III] products which are slowly converted to the final cobalt [III] supports an inner-sphere mechanism for the oxidation of the complex by both oxidants. Under identical experimental conditions, the extent of oxidation using the oxidizing agents is in the order: NBS > NBP. GC-MS analysis for the reaction mixture after completion of the oxidation reaction indicates the presence of both succinimide and phthalimide as side products of the oxidation process

N-bromosuccinimide as an analytical reagent for the determination of some antihypertensive agents

Oxprenolol hydrochloride, captopril nadolol, indapamide and atenolol are quantified using N-bromosuccinimide. The method depends on both direct titration using methyl red indicator and indirect iodometric titration. The stoichiometry of the reaction is ascertained in each case. The methods are successfully applied for the determination of the mentioned drugs in their tablet formulation

Utilization of N-halouccinimide for semi-microdetermination of azapropazone in bulk powder and pharmaceutical formulations

The utilization of N-bromosuccinimide [NBS] and N-chlorosuccinimide [NCS] for titrimetric determination of anti-inflammatory drug azapropazone was described. The study of stoichiometry of the reactions revealed that 1 mole of azapropazone reacts with 4 moles NBS and 2 moles of NCS. The optimum time for complete the reaction was found to be 10 minutes in cases of NBS and NCS. The method was successfully applied for the determination of azapropazone in bulk powder and prolixan capsules. The reaction product of azapropazone with NBS was isolated and investigated by instrumental analysis and reaction pathway was proposed. Also, suggested reaction pathway for investigated drug with NCS was proposed

Utilization of N-bromosuccinimide and N-chlorosuccinimide for colorimetric determination of azapropazone in bulk powder and capsules

Two simple and accurate procedures are described for colorimetric determination of anti-inflammatory drug, azapropazone. The procedures involve the use of N-bromosuccinimide [NBS] and N-chlorosuccinimide [NCS] for determining azapropazone in bulk powder and pharmaceutical formulation. The optimum reactions conditions were studied. In the first procedure, azapropazone was dissolved in ethanol, treated with NBS solution [1%, 5 ml] and sulfuric acid [5 ml]. The red color produced exhibits and absorption maximum at 488 nm. Different concentrations ranging from 80 to 320 muml-1 of azapropazone were measured. In the second procedure, the yellow color developed upon the treatment of azapropazone with NCS solution [0.5%, 2 ml] in different media exhibits an absorption maximum at 451 nm. Linearity of the absorbance of yellow color versus the concentration of azapropazone was verified in the ranges 5-50, 20-100 mug m1-1 for aqueous, acidic and basic media, respectively. Both procedures described here were applied for the determination of azapropazone in the pure state and in prolixan capsules. The procedures proposed here are precise and reproducible

Quantitative determination of cimetidine and ranitidine using n-bromosuccinimide [NBS]

A simple and accurate titrimetric method was developed for the determination of cimetidine and ranitidine. It involved direct titration of the mentioned drugs with NBS using methyl red as indicator. The stoichiometry for each drug was ascertained. The reaction pathways and products between NBS, cimetidine and ranitidine hydrochloride were suggested. The method was applied successfully for the determination of the investigated drugs in their pharmaceutical dosage forms. The validity of the method was checked by applying the st and ard addition technique. Compared with the official USP XXII assay of cimetidine, the method is simple, rapid and highly sensitive

Determination of some benzodiazepines using N-bromosuccinimide: part I-litrimetric methods

Diazepam, lormetazepam, chlorodemethyldiazepam and lorazepam representing 1,4-benzodiazepines are quantified using N- bromosuccinimide after being hydrolyzed in aqueous hydrochloric or sulfuric acids. The stoichiometry of the reaction is ascertained in each medium. Clobazam, a 1,5-benzodiazepine, is estimated by reaction of the intact drug in 1: 9 DMF/4 M HCl with N-bromosuccinimide. The methods presented are successfully applied for the determination of the aforementioned drugs in their pharmaceutical formulations

Determination of some benzodiazepines using N-bromosuccinimide: part II: spectrophotometric methods

A spectrophotometric determination of diazepam and lormetazepam based on measuring the absorbance of the corresponding benzophenones N- bromosuccinimide reaction products is presented. The method is capable of determining hydrolyzed diazepam or lormetazepam when present in mixture with the intact drug. The methods presented are successfully applied for the determination of the aforementioned drugs in their pharmaceutical formulations

Titrimetric determination of piroxicam and diclofenac sodium using N-bromosuccinimide

A simple volumetric method for the determination of each of piroxicam and diclofenac sodium is suggested based on the reaction with N- bromosuccinimide [NBS]. The direct titration with NBS is only successful for piroxicam in glacial acetic acid medium using methyl orange as indicator. However, the indirect titration is described for both piroxicam and diclofenac sodium, in which the drug solution is allowed to react with a known excess of standard NBS solution for the specified time and the excess NBS is back titrated iodometrically. The different factors affecting the titrations are discussed. The method determines 1.2 mg of piroxicam in the direct titration with a mean accuracy of 100.4 +/- 1.03% and determines 2-12 mg of piroxicam and 1-15 mg of diclofenac sodium in the indirect titration with mean accuracies of 100.0 +/- 0.53% and 100.1 +/- 0.78%, respectively

Spectrophotometric determination of sulphonamides with metol and n-chlorosuccinimide [NCS], Dibromohydantoin [DBH] or N-Bromosuccinimide [NBS]

Ten sulfonamides are determined by interaction with NCS or DBH together with metol and measurement of the purplered color produced at 520 nm. These sulfonamides are: sulfacetamide sodium, sulfamethoxazole, sulfaguanidine, sulfadimidine, sulfamethoxypyridazine, sulfamethoxydiazine, sulfaphenazole, sulfathiazole, phthalylsulfathiazole and succinylsulfathiazole. NBS is also used in conjuction with metol with the last five sulfonamides, not determined before by this procedure. The reaction is explained as involving oxidation of metol with NCS or DBH to p-N- methybenzoquinoneimine, followed by the formation of a purple red complex with the sulfonamide