Sensitive and rapid titrimetric and spectrophotometric methods for the determination of stavudine in pharmaceuticals using bromate-bromide and three dyes
Document title: Sensitive and rapid titrimetric and spectrophotometric methods for the determination of stavudine in pharmaceuticals using bromate-bromide and three dyes
Journal: Anais da Academia Brasileira de Ciencias
Database: PERIÓDICA
System number: 000364858
ISSN: 0001-3765
Authors: 1
2
1
1
Institutions: 1University of Mysore, Department of Chemistry, Manasagangotri, Mysore. India
2Government College of Pharmacy, Department of Drugs Control, Bangalore, Karnataka. India
Year:
Season: Jun
Volumen: 80
Number: 2
Pages: 253-262
Country: Brasil
Language: Inglés
Document type: Artículo
Approach: Analítico, descriptivo
English abstract Four sensitive and rapid methods for the determination of stavudine (STV) in bulk drug and in dosage forms were developed and optimized. In titrimetry, aqueous solution of STV was treated with a known excess of bromate-bromide in HCl medium followed by estimation of unreacted bromine by iodometric back titration. Spectrophotometric methods involve the addition of a measured excess of bromate-bromide in HCl medium and subsequent estimation of the residual bromine by reacting with a fixed amount of methyl orange, indigocarmine or thymol blue followed by measurement of absorbance at 520 nm (method A), 610 nm (method B) or 550 nm (method C). In all the methods, the amount of bromate reacted corresponds to the amount of STV. Calculations in titrimetry were based on a 1:0.666 (STV:KBrO3) stoichiometry and the method was found to be applicable over 3.5-10 mg range. A linear increase in absorbance with concentration of STV was observed in the spectrophotometric methods, and the Beer's law was obeyed over the concentration ranges 0.125-1.75, 1-10 and 1-9.0 µg mL-1 STV for method A, method B and method C, respectively. The methods when applied to the determination of STV in tablets and capsules were found to give satisfactory results
Portuguese abstract Este trabalho descreve quatro métodos rápidos e sensíveispara a determinação de estavudina (STV) na matéria-prima ou em produtos formulados. Soluções aquosas de STV podem ser tituladas tratando-as com excesso de bromato-brometo em meio ácido clorídrico, seguido da determinação iodimétrica de bromo em excesso. Métodos espectrofotométricos tambémenvolvem a adição de excesso de bromato-brometo à amostra, seguida da determinação de bromo residual por adição de uma quantidade fixa de alaranjado de metila, índigo-carmim ou azul de timol, e de medidas de absorbância nos comprimentos de onda apropriados: 520, 610 ou 550 nm. Em todos os métodos, a quantidade de bromato consumida corresponde à quantidade de STV e os resultados da sua aplicação à determinação de STV em comprimidos e cápsulas são satisfatórios
Disciplines: Química
Keyword: Química farmacéutica,
Espectrofotometría,
Estavudina,
Análisis químico
Keyword: Chemistry,
Medicinal chemistry,
Spectrophotometry,
Stavudine,
Chemical analysis
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