Flow-injection iodimetric determination of captopril in pharmaceutical preparations

Abstract

Um procedimento simples, rápido e de baixo custo é descrito para a determinação de captopril em preparações farmacêuticas. O procedimento é baseado em um sistema de análises por injeção em fluxo explorando a formação em linha de triiodeto, o qual é consumido na presença do analito gerando um sinal transiente. Resposta linear foi observada até 200 µmol L -1 com limite de detecção de 1,0 µmol L -1 (99,7% de confiança). O coeficiente de variação (n = 20) e a freqüência de amostragem foram estimados em 1,2% e 72 determinações por hora, respectivamente. Os principais excipientes encontrados em preparações farmacêuticas não afetaram a determinação de captopril. Reamostragem na zona dispersa foi explorada para implementar diluições em linha, visando a análise direta de suspensões das amostras. Resultados da análise de amostras comerciais foram concordantes com os obtidos pelo procedimento volumétrico de referência descrito na Farmacopéia americana com nível de confiança de 95%. O consumo de reagente foi estimado em 18 µg KMnO 4 e 10 mg KI por determinação, com custo de US$ 2,50 por 1000 determinações.A simple, fast and low cost procedure for spectrophotometric determination of captopril in pharmaceutical preparations is described. The procedure is based on a flow-injection system exploiting the on-line formation of the triiodide reagent, which is consumed in the presence of the analyte generating a transient signal. Linear response was observed up to 200 µmol L -1 with a detection limit of 1.0 µmol L -1 (99.7% confidence level). The coefficient of variation (n = 20) and the sampling rate were estimated as 1.2% and 72 determinations per hour, respectively. The main excipients found in pharmaceutical preparations did not affect the captopril determination. The zone sampling approach was exploited to implement on-line dilutions, aiming direct analysis of sample extracts. Results of the analysis of commercial samples agreed with the obtained by the titrimetric reference procedure described in the US-Pharmacopeia at the 95% confidence level. The reagent consumption was estimated as 18 µg of KMnO 4 and 10 mg of KI per determination, with a cost of US$ 2.50 per 1000 determinations.

A Novel Use of 3-Methyl-2-Benzothiazolinone Hydrazone Hydrochloride Monohydrate for Kinetic Spectrophotometric Determination of Captopril in Pharmaceutical Formulations

“…About 30% of the drug is bound to plasma protein [2][3]. In order to assure the quality of CPT containing pharmaceutical formulations, several analytical methods have been reported for its determination, including spectrophotometric [4][5][6][7][8][9], kinetic spectrophotometric methods [10][11][12][13], high performance liquid chromatography (HPLC) [14][15][16], polarography [17], stripping voltammetry [18][19], fluorimetry [20], atomic absorption spectrophotometry [21], flow injection analysis [22][23][24][25],and potentiometry [26].…”

Development of a new procedure for the determination of captopril in pharmaceutical formulations employing chemiluminescence and a multicommuted flow analysis approach

“…Because of its importance for human health, a variety of analytical procedures for its determination have been proposed, employing separation techniques such as high‐performance liquid chromatography (HPLC) and capillary electrophoresis . The following procedures have been employed as detection techniques: voltammetry , spectrophotometry and chemiluminescence .…”

Flow-injection spectrophotometric determination of captopril in pharmaceutical formulations using a new solid-phase reactor containing AgSCN immobilized in a polyurethane resin

“…Methods based on titrimetric (Mohamed et al, 1983;Basavaiah, Prameela, 2004;Schmidt et al, 2009), spectrophotometric Suarez et al, 2009;Suarez et al, 2011), fluorimetric (Al-Ghannam et al, 2002;Chen, Cai, 2003), amperometric (Marcolino-Junior et al, 2009), conductometric (Lourenção et al, 2008), voltammetric (Ziyatdinova et al, 2006Rezaei, Damiri, 2008;Karimi-Maleh et al, 2010), and chemiluminescence (Pulgarín et al, 2005) procedures have been previously described. The Brazilian Pharmacopeia recommends an iodimetric method for the determination of captopril in pharmaceutical formulations (Farmacopéia Brasileira, 1977).…”