RESUMO
A simple, sensitive, rapid and accurate spectrophotometric method was developed for the determination of risedronate, a bisphosphonate drug important for the treatment of a variety of bone diseases, in raw material and pharmaceutical formulations. The proposed method is based on complex formation between risedronate and Cu (II) ions in acetate buffer of pH5.5. The optimum conditions for this reaction were ascertained and a spectrophotometric method was developed for the determination of risedronate in concentration range of 2-40 µg/mL with detection limit of 0.03 µg/mL (9.51 × 10(-8) mol/L). The molar absorbtivity was 8.00 × 10(3) l/mol/cm. The method was successfully applied for the determination of risedronate in tablet dosage form with mean percentage recovery of 101.04 ± 0.32. The results obtained were favorably compared with those obtained by the comparison method. Furthermore, the proposed method was applied for content uniformity testing of risedronate tablets.
RESUMO
A simple spectrophotometric method was developed for the determination of penicillamine and carbocisteine. The method depends on complexation of penicillamine with Ni, Co and Pb ions in acetate buffer pH of 6.3, 6.5 and 5.3, respectively, and carbocisteine with Cu and Ni ions in borate buffer pH of 6.7; 1-70 microg/ml of these drugs could be determined by measuring the absorbance of each complex at its specific lambdamax. The results obtained are in good agreement with those obtained using the official methods. The proposed method was successfully applied for the determination of these compounds in their dosage forms. Also, the molar ratio and stability constant of the metal complexes were calculated and a proposal of the reaction pathway was postulated.
Assuntos
Carbocisteína/química , Metais Pesados/química , Compostos Organometálicos/síntese química , Penicilamina/química , Análise Espectral/métodos , Acetatos/química , Boratos/química , Cápsulas/análise , Cápsulas/química , Carbocisteína/isolamento & purificação , Interpretação Estatística de Dados , Estabilidade de Medicamentos , Concentração de Íons de Hidrogênio , Hidróxidos/síntese química , Íons , Substâncias Macromoleculares/química , Metais Pesados/classificação , Metais Pesados/farmacocinética , Estrutura Molecular , Compostos Organometálicos/isolamento & purificação , Penicilamina/isolamento & purificação , Análise Espectral/tendências , Fatores de Tempo , TurquiaRESUMO
A kinetic spectrophotometric method was developed for the determination of carbocisteine, ethionamide, thioctic acid and penicillamine based on the catalytic effect on the reaction between sodium azide and iodine in aqueous solution. Ten to 100 microg ml(-1) of carbocisteine and ethionamide, 0.1-1 microg ml(-1) of thioctic acid and 0.01-0.1 microg ml(-1) of penicillamine could be determined, respectively, by measuring the decrease in the absorbance of iodine at 348 nm by a fixed time method. The decrease in the absorbance in the first 5 min from the initiation of the reaction is related to the concentration of the drugs. The detection limits were 0.47, 0.71, 0.018 and 9.38 x 10(-4) microg ml(-1) for the four drugs, respectively. The proposed procedure was successfully applied in the determination of these drugs in pharmaceutical preparations and human serum.
