RESUMO
New, accurate and reliable spectrophotometric methods for the assay of three statin drugs, atorvastatin calcium (AVS), fluvastatin sodium (FVS) and pravastatin sodium (PVS) in pure form and pharmaceutical formulations have been described. All methods involve the oxidative coupling reaction of AVS, FVS and PVS with 3-methyl-2-benzothiazolinone hydrazone hydrochloride monohydrate (MBTH) in the presence of Ce(IV) in an acidic medium to form colored products with λ(max) at 566, 615 and 664 nm, respectively. Beer's law was obeyed in the ranges of 2.0-20.0, 4.9-35.4 and 7.0-30.0 µg mL(-1) for AVS-MBTH, FVS-MBTH and PVS-MBTH, respectively. Molar absorptivities for the above three methods were found to be 3.24×10(4), 1.05×10(4) and 0.68×10(4) L mol(-1) cm(-1), respectively. Statistical treatment of the experimental results indicates that the methods are precise and accurate. The proposed methods have been applied to the determination of the components in commercial forms with no interference from the excipients. A comparative study between the suggested procedures and the official methods for these compounds in the commercial forms showed no significant difference between the two methods.
Assuntos
Química Farmacêutica/métodos , Inibidores de Hidroximetilglutaril-CoA Redutases/química , Acoplamento Oxidativo , Espectrofotometria/métodos , Atorvastatina , Formas de Dosagem , Excipientes/química , Ácidos Graxos Monoinsaturados/química , Fluvastatina , Ácidos Heptanoicos/química , Indóis/química , Estrutura Molecular , Oxirredução , Pravastatina/química , Pirróis/químicaRESUMO
Simple, accurate and reliable kinetic spectrophotometric method for the determination of fluvastatin sodium (FVS) in pure form and pharmaceutical formulations has been described. The method is based on the formation of colored product between FVS and 4-chloro-7-nitrobenzofurazan (NBD-Cl) in acetone medium at 55 ± 2ºC. The reaction is followed spectrophotometrically by measuring the increase in absorbance at 462 nm as a function of time. The rate data and fixed time methods were adopted for constructing the calibration curves. The linearity ranges were found to be 15.0-50.0 and 10.0-90.0 µg mL(-1) for rate data and fixed time methods, respectively. The limit of detection for rate data and fixed time methods is 0.017 and 0.134 µg mL(-1), respectively. The proposed methods have been successfully applied to the determination of fluvastatin sodium in pharmaceutical dosage forms with no interference from the excipients. Statistical comparison of the results shows that there is no significant difference between the proposed and official methods.
