Two spectrophotometric methods were developed and validated for the determination of rifampicin (RIF) in bulk form, formulations, and spiked human urine. The first method is based on the reduction of ...the Folin–Ciocalteu (FC) reagent by RIF to form a blue colored chromogen with λ
max
at 760 nm (the FCR method). In the second method, iron(III) is reduced by RIF in a neutral medium, and the resulting iron(II) is complexed with ferricyanide to form a Prussian blue peaking at 750 nm (the FFC method). Under optimum conditions, Beer's law enabled the determination of the drug in the concentration ranges 1–35 and 2.5–50 μg/mL with apparent molar absorptivities of 2.72 × 10
4
and 1.63×10
4
L/(mol × cm) for the FCR and FFC methods, respectively. The Sandell sensitivity, limits of detection (LOD), and quantification (LOQ) values were also reported for both methods. The precision of the methods, with % RSD of < 2%, was satisfactory, and the accuracy was higher than 2% (RE). The proposed methods were successfully applied to the determination of drug in capsules without interference from common additives and spiked human urine without interference from endogenous substances. A statistical analysis indicated that there was no significant difference between the results obtained by the developed methods and the official method.
Two spectrophotometric methods for the estimation of ropinirole hydrochloride (RP) in bulk drug and in its tablet formulations are described. Method A based on charge transfer (CT) interactions ...between RP as amino heterocyclic donor and chloranilic acid (CLA) as π-acceptor showing absorption maximum at 528 nm. Factors controlling the CT-reactions were studied, optimized and composition of the formed CT-complexes was identified. Job's method of continuous variation was used to detect the stoichiometric ratios of the formed complexes and they showed that 1:1 complexes were produced between RP and CLA. Also the solid CT-complexes were characterized by FTIR spectroscopy where the formed complexes included proton and electron transfer. The method B is based on the formation of blue colored chromogen due to the reaction of RP with Folin Ciocalteu (FC) reagent in presence of alkali which exhibits an absorption maximum at 633 nm. Beer's law range is 1-100 μg /ml and 5-40 μg /ml for methodA and method B respectively. Under the optimum conditions, linear relationships with good correlation coefficients were identified with high accuracy and precision. The proposed methods were successfully applied to the determination of RP in formulations.
Two simple, sensitive, accurate, rapid, and economical spectrophotometric methods have been developed for the estimation of diacerein in Pharmaceutical dosage forms. Method A is based on the reaction ...of diacerein with Folin-Ciocalteu reagent, in the presence of 0.5 N sodium hydroxide solution, giving a pink-colored chromogen, which shows maximum absorbance at 512 nm against reagent blank, while method B is based on the oxidation of diacerein with potassium permanganate in an alkaline medium giving a pink-colored chromogen, which shows maximum absorption at 497.5 nm. Beer′s law was obeyed in the concentration range of 4 - 20 μg/ml for both methods A and B. Results of the analysis were validated statistically, and by recovery studies.
A simple accurate reproducible spectrophotometric method was established for the estimation of Flucloxacillin sodium based on oxidative coupling reaction. The method is based upon formation of light ...green colored product formed, when drug reacts with Folin-ciocalteu reagent (F.C). The coloured species has absorption maximum at 912 nm and obeys Beer’s law in the concentration range of 0.05-0.25mg/ml. The optimum experimental parameters have been studied. Statistical analysis of the results has been carried out revealing high accuracy and good precision. The proposed method was successfully applied for the determination of Flucloxacillin in pharmaceutical formulations.
Two simple, sensitive and reproducible spectrophotometric methods (Method A and B) were developed for the determination of Ziprasidone in bulk and in tablet dosage forms. Method A is based on ...reduction of Folin-Ciocalteau reagent by the drug Ziprasidone Hydrochloride in the presence of sodium bicarbonate to form a blue colored chromogen having maximum absorption at 436 nm. Method B is based on the oxidation of the drug by potassium ferricyanide reagent to form a blue colored chromogen having maximum absorption at 733 nm. Beer’s law is obeyed in the range of 0.5 – 3 and 1-5 μg/ml for Method A & B respectively. Results of analysis were validated statistically and by recovery studies. These Methods are successfully employed for the determination of Ziprasidone in various pharmaceutical tablet dosage forms.
Antioxidant activity and verbascoside content in extracts from two uninvestigated endemic Plantago spp Gonalves, Sandra; Toms GrevenstukauthorFaculty of Sciences and Technology, MeditBio University of Algarve, Campus de Gambelas, Ed. 8, 8005-139 Faro, Portugal; Neusa MartinsauthorFaculty of Sciences and Technology, MeditBio University of Algarve, Campus de Gambelas, Ed. 8, 8005-139 Faro, Portugal ...
2015
Journal Article
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