Flow-Injection Chemiluminescence Determination of Enalapril Maleate in Pharmaceuticals and Biological Fluids Using Tris(2,2′-bipyridyl)ruthenium(II)

Abstract

Enalapril maleate is a relatively new oral angiotensinconverting enzyme (ACE) inhibitor. Enalapril maleate, like its first-generation relative, captopril, has been shown to be effective in the treatment of hypertension and congestive heart failure. Enalapril [(S)-1-(N-[1-(ethoxycarbonyl)-3-phenylpropyl]-Lalanyl)-L-proline] is a prodrug which is de-esterified in the hepatic system to an active diacid form. 2 The drug is official in the USP 24. 3 The methods of analysis of the bulk drug and its tablets are high-performance liquid chromatography (HPLC) methods. It is also official in the European Pharmacopoeia 4 by a potentiometric titration method using sodium hydroxide.Other than the published analytical profile, 5 several methods have been reported for the analysis of enalapril maleate either in pure form, in pharmaceutical preparations, in biological fluids, or in mixture with other drugs. These include spectrophotometric methods, 33 Reviewing the literature revealed that up to the present time nothing has been published concerning the CL determination of enalapril maleate.Ru(bipy) 3 2+ is an extremely versatile base reactant for a variety of CL processes, and has also recently become a useful CL reagent. The process involves the oxidation of Ru(bipy)3 2+to Ru(bipy) 3 3+ , which is then followed by reduction with an analyte species to produce the emission of light. 34 There have been a variety of methods employed to obtain the active oxidized reagent Ru(bipy) 3 3+ .These include chemical, photochemical, electrochemical oxidation and in situ electrochemiluminescence.An analytical evaluation of commercially significant pharmaceutical drugs using Ru(bipy) 3 3+-CL detection has attracted considerable attention. A comprehensive review of the analytical applications of Ru(bipy) 3 3+ as a chemiluminescent reagent from 1978 to mid 1998 has been represented by Gerardi et al. 34The present paper describes the development of a simple flow-injection chemiluminometric method for the determination of enalapril maleate based on the chemical generation of Ru(bipy) 3 3+ by mixing two streams containing solutions of Ru(bipy) 3 2+ and acidic KMnO4. The experimental conditions for the reaction were optimized, and the final procedure allowed the successful determination of the studied drug in pharmaceuticals and biological fluids. Experimental Apparatus and manifoldThe flow system used for the determination and CL detection of enalapril maleate is shown schematically in Fig. 1. It consisted of a Gilson Minipuls 3MP4 peristaltic pump (two channels, variable speed) which was used to drive the carrier and the reagent streams through the flow system. Each stream was pumped at a constant flow rate using PTFE tubing (0.8 mm i.d.). The drug solution (250 µl) was injected through the sample injection valve, which allowed mixing of the sample with an acidified 1 × 10 -3 mol/l KMnO4 solution, and then combination with a 1 × 10 -2 mol/l Ru(bipy) 3 2+ solution in a Tshaped piece before entering the flow cell. The flow cell was a coil made of ...

Flow-injection chemiluminescent determination of cefprozil using Tris (2,2′-bipyridyl) ruthenium (II)-permanganate system

“…The reproducibility, selectivity and rapidity in signal detection of CL analysis can be highly improved by combination with FI technique [13][14][15][16][17].…”

Determination of enalapril maleate and atenolol in their pharmaceutical products and in biological fluids by flow‐injection chemiluminescence

“…The high sensitivity attained by the proposed method allows the determination of the studied drugs in biological fluids. The extraction procedure for biological fluids was performed using dichloromethane, which was chosen as the best extraction solvent for enalapril maleate, [50] and chloroform/2-propanol mixture (4:1, v/v) as the suitable extraction solvent for atenolol.…”

“…These include spectrophotomety, [30][31][32] flow-injection spectrophotomety, [33] fluorimetry, [34] 1 HNMR, [35] IR, [36] amperometry, [37,38] potentiometry, [39,40] polarography, [30] TLC, [41] GC, [42] GC/MS, [43] HPLC/UV detection, [44,45] HPLC/MS, [46] HPLC/MS/ MS, [47] CZE, [48] MEKC [49] and a flow-injection chemiluminescence method, [50] which is based on the CL reaction of the drug with tris(2,2′-bipyridyl)ruthenium(II), Ru(bipy) 3 2+ and acidic potassium permanganate. Calibration graphs were obtained over concentration ranges of 0.005-0.2 and 0.7-100 μg mL −1 with a detection limit (S/N = 2) of 0.001 μg mL .…”

“…Calibration graphs were obtained over concentration ranges of 0.005-0.2 and 0.7-100 μg mL −1 with a detection limit (S/N = 2) of 0.001 μg mL . [50] The attractiveness of tha proposed 423 analytical procedure applying chemiluminescence (CL) coupled with flow-injection analysis (FIA) is not only the simplicity and sensitivity of detection but also that the reagents used here are cheaper than those reported previously.…”

Development and Validation of a Liquid Chromatographic Method for the Analysis of Positron Emission Tomography Radiopharmaceuticals with Ru(bpy)32+-KMnO4 Chemiluminescence Detection

“…KMnO4 was selected as the oxidant, since it has been shown to be effective and easy to use. 14,15 The influence of the concentration of KMnO4 on the detector response was different for the 4 compounds tested (Fig. 4B).…”