Determination and rotamer separation of enalapril maleate by capillary electrophoresis

Qin, Xue-Zhi; Ip, Dominic P.; Tsai, Eric W.

doi:10.1016/0021-9673(92)85417-r

Cited by 58 publications

(18 citation statements)

References 21 publications

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“…Rotation about the amide bond between the two amino acids gives rise to a characteristic elution profile in the electrophoretic separation of enalaprilat. As the cis-trans interconversion occurs within the time scale of partitioning, a plateau formation between the two separated peaks of the isomers can be observed [95]. The first kinetic investigation was done by Trapp et al [96].…”

Section: Drugsmentioning

confidence: 98%

“…The elution order of the peaks was assigned according to the findings of Qin et al [95] and Kocijan et al [97] that the predominating cis-enalaprilat has a larger hydrophobic surface area and therefore interacts better with SDS micelles and stationary phases on RP chromatographic columns. Therefore, the elution order of the isomers should be trans before cis according to IUPAC rules [98].…”

Section: Drugsmentioning

confidence: 99%

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Investigation of the stereodynamics of molecules and catalyzed reactions by CE

Trapp

2010

Electrophoresis

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The investigation of the molecular dynamics of stereoisomers and the study of the kinetics of reactions, in particular of catalyzed reactions, is of fundamental interest in chemistry, biochemistry, and medicine. Understanding how to control the transition state of a reaction allows for a directed design of new catalysts and benign processes. The integration of reactions and capillary or microchip-based electrophoretic separations is highly attractive to perform on-column derivatizations or enzymatic on-column digests of peptides and proteins for further characterization. The present review article focuses on the recent advances to study the stereodynamics of molecules and reaction kinetics of catalyzed processes by means of CE. Models and algorithms to evaluate interconversion profiles obtained by electrophoretic separation techniques are discussed with respect to the challenging demands of high separation efficiencies typical for electrophoretic techniques. Models used for evaluation are based on iterative computer simulation algorithms using the theoretical plate model or stochastic model of chromatography, empirical calculation methods, derived from equations used in chemical engineering, namely Damköhler analysis, and direct access with the approximation function and more recently with the unified equation, which can be applied to all kinds of first-order reactions taking place during a chromatographic or a electrophoretic separation. Furthermore, areas of applications are presented and discussed to give a guideline for using dynamic CE and on-column reaction electrophoresis to study kinetics of reactions and dynamic processes.

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Section: Drugsmentioning

confidence: 98%

Section: Drugsmentioning

confidence: 99%

Investigation of the stereodynamics of molecules and catalyzed reactions by CE

Trapp

2010

Electrophoresis

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“…It was found that in the investigated temperature range the ratio of the peaks of the two isomers is temperature-dependent and the peak area of the first eluted isomer decreases with increasing temperature. The elution order of the peaks was assigned according to the findings of Qin et al [22] and Kocijan et al [47] that the predominating cis-enalaprilat has a larger hydrophobic surface area and therefore interacts better with SDS micelles and stationary phases on RP chromatographic columns. Therefore, the elution order of the isomers should be trans before cis.…”

Section: Separationmentioning

confidence: 99%

“…Fig. 1) has been previously described by several authors using HPLC [20,21] and CE [22]. All authors describe the characteristic elution …”

mentioning

confidence: 90%

Determination of the cis‐trans isomerization barrier of enalaprilat by dynamic capillary electrophoresis and computer simulation

Trapp

Schurig

2004

Electrophoresis

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Dynamic capillary electrophoresis (DCE) and computer simulation of the elution profiles with the stochastic model has been applied to determine the isomerization barriers of the angiotensin converting enzyme inhibitor enalaprilat. The separation of the rotational cis-trans isomeric drug has been performed in an aqueous 20 mM borate buffer at pH 9.3. Interconversion profiles featuring plateau formation and peak broadening were observed. To evaluate the rate constants k(cis-->trans) and k(trans-->cis) of the cis-trans isomerization from the experimental electropherograms obtained by dynamic capillary electrophoresis, elution profiles were analyzed by a simulation with iterative convergence to the experimental data using the ChromWin software which requires the total migration times of the individual isomers t(R), the electroosmotic break-through time t(0), the plateau height h(plateau), the peak widths at half height of the individual isomers w(h), as well as the peak ratio of the isomers as experimental data input. From temperature-dependent measurements between 0 degrees and 15 degrees C the thermodynamic parameters Delta G, Delta H and Delta S, the rate constants k(cis-->trans) and k(trans-->cis) and the kinetic activation parameters Delta G*, Delta H*, and Delta S* of the cis-trans isomerization of enalaprilat were obtained. From the activation parameters the isomerization barriers at 37 degrees C were calculated to be Delta G* (trans-->cis) = 87.2 kJ.mol(-1) and Delta G*(cis-->trans) = 91.9 kJ.mol(-1).

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“…These include spectrophotometric methods, [6][7][8][9] flow-injection spectrophotometric, 10 infrared method, 11 potentiometric selective membrane electrode methods, 12,13 NMR, 14 GC, 15 GCL/MS, 16 HPLC, [17][18][19][20][21][22][23][24][25][26][27] capillary electrophoresis, [28][29][30][31] radioenzymic 32 and radioimmunoassay. 33 Reviewing the literature revealed that up to the present time nothing has been published concerning the CL determination of enalapril maleate.…”

Section: Enalapril [(S)-1-(n-[1-(ethoxycarbonyl)-3-phenylpropyl]-lalamentioning

confidence: 99%

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

Alarfaj

2003

ANAL. SCI.

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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 ...

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Determination and rotamer separation of enalapril maleate by capillary electrophoresis

Cited by 58 publications

References 21 publications

Investigation of the stereodynamics of molecules and catalyzed reactions by CE

Investigation of the stereodynamics of molecules and catalyzed reactions by CE

Determination of the cis‐trans isomerization barrier of enalaprilat by dynamic capillary electrophoresis and computer simulation

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

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