A simple spectrophotometric method for the determination of captopril in pharmaceutical preparations using ammonium molybdate

Abstract

A simple, rapid and sensitive spectrophotometric method for the determination of captopril (CPT) in pharmaceutical formulations is proposed. This method is based on the reduction reaction of ammonium molybdate, in the presence of sulphuric acid, for the group thiol of CPT, producing a green compound (λmax 407 nm). Beer’s law is obeyed in a concentration range of 4.60 x 10-4 – 1.84 x 10-3 mol l-1 of CPT with an excellent correlation coefficient (r = 0.9995). The limit of detection and limit of quantification were 7.31 x 10-6 e 2.43 x 10-5 mol l-1 of CPT, respectively. The proposed method was successfully applied to the determinationof CPT in commercial brands of pharmaceuticals. No interferences were observed from the common excipients in the formulations. The results obtained by the proposed method were favorably compared with those given by the official reported method at 95 % confidence level.

Direct Synthesis of Pure Ammonium Molybdates from Ammonium Tetramolybdate and Ammonium bicarbonate

“…In addition, molybdate can be used as a corrosion inhibitor, which plays an important role in the corrosion delay of metals , or used in the manufacture of molybdenum-containing catalysts. − Wang et al added 2 wt % of (NH 4 ) 6 Mo 7 O 24 to the ceramic tile polishing waste and heated at 1200 °C for 30 min to prepare foam ceramics with excellent properties . Riberio et al proposed a method for determining captopril in pharmaceutical formulations by using the reduction reaction of ammonium molybdate . Nikolenko et al presented a method for preparing iron molybdate catalysts by using ammonium molybdate and iron­(II) as precursors …”

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].…”