Flow-Injection Spectrophotometric Determination of Captopril Exploiting Silver Chloranilate Solid-Phase Reactor

Abstract

A novel, simple, and rapid flow-injection method for the spectrophotometric determination of captopril in pharmaceutical products, using a solid-phase reactor with silver chloranilate (Ag 2 C 6 Cl 2 O 4 ) immobilized in a polyester resin, is presented. This method explored the formation of an insoluble salt between Ag(I) and captopril in the solid-phase reactor, releasing chloranilate anion (C 6 Cl 2 O 2À 4 ). Then, this anion reacted with ferric ions to produce a complex, FeC 6 Cl 2 O þ 4 , which was monitored spectrophotometrically at 528 nm. The analytical curve was linear in the captopril concentration range from 1.0 Â 10 À5 to 5.0 Â 10 À4 mol l À1 with a detection limit of 8.0 Â 10 À6 mol l À1 . The relative standard deviation (RSD) was 0.35% (n ¼ 10) for a solution of 3.0 Â 10 À4 mol l À1 captopril solution, and an analytical frequency of 70 h À1 was obtained. The effects of excipients frequently found with captopril in pharmaceutical formulations, such as lactose, microcrystalline cellulose, starch, and magnesium stearate, were evaluated using the proposed flow-injection method. None of these substances caused significative interference 973 in the proposed method. The method was successfully applied to the determination of captopril in pharmaceutical products, and the results were compared with results obtained using a potentiometric method.

Nitroprusside as a Novel Reagent for Flow Injection Spectrophotometric Determination of Captopril

“…Alternative methods based on FIA have already been reported, involving voltammetry (Marcolino-Junior et al 2009;Siangproh, Ngamukot, and Chailapakul 2014), spectrophotometry Rocha 2009, 2011;Suarez et al 2009Suarez et al , 2011, and chemiluminesce (Rodrigues and Santos 2012).…”

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

“…Several procedures, utilizing solid-phase reactors that are based on the immobilization of insoluble salts such as Zn 3 (PO 4 ) 2 , Ag 2 C 6 Cl 2 O 4 (Suarez et al 2009), Fe(OH) 3 , CoCO 3 (Icardo et al, 1998;Corominas et al, 2005), AgCl (Marcolino-Junior et al, 2005), and PbO 2 (Teixeira et al, 2002) in a polymeric matrix have been described in the literature. A typical immobilization procedure involves mixing the salt with polyester resin followed by the addition of a catalyst (methylethyl ketone).…”

“…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).…”

Analytical chemistry in Brazil: healthy and growing

“…Another flow-based procedure for determination of the anti-hypertensive used a solid-phase reactor with silver chloranilate immobilized in polyester resin and detection of the chloranilate released in the presence of the analyte by complex formation with Fe(III). 220 A flow injection system with pulsed amperometric detection was used for simultaneous determination of paracetamol and dypirone with an analytical throughput of 45 determinations per hour. 221 Simultaneous determination was carried out by fast sequentially applying potential pulses: +0.40 V for detection of dypirone and +0.65 V to generate the oxidation product N-acetyl-p-benzoquinoneimine, whose reduction at 0 V is used for indirect determination of paracetamol.…”