Multiple peak formation in reversed-phase liquid chromatography of ramipril and ramiprilate

Stability of ramipril in the solvents of different pH

“…The single peak of ramipril is obtained on the chromatogram, when the separation run on C18 column. Unlike the use of cation-exchange column, where the elution of ramipril as a bimodal, broad peak may be due to a difference in acidity for the cis-and trans-rotamers [4].…”

“…Ramipril, an angiotensin-converting enzyme inhibitor, is a prodrug which is rapidly hydrolysed after absorption to the active metabolite ramiprilate. The cis-and transisomers of ramiprilate were investigated by nuclear magnetic resonance studies [4,5]. A radioimmunoassay (RIA) has been developed for the measurement ramipril and its active metabolite (diacid: hydrolysis product of ramipril) in serum or plasma.…”

Kinetic study on the epimerization of trityloxymethyl butyrolactol by liquid chromatography

“…This chemical interconversion can occur during sample preparation or on-column and may be influenced by the mobile phase or the stationary phase. The types of reactions that may occur include acid or base catalyzed reactions and isomerization [20][21][22][23][24][25][26][27].…”

Simultaneous quantitation of enalapril and enalaprilat in human plasma by 96‐well solid‐phase extraction and liquid chromatography/tandem mass spectrometry

“…Enalapril is metabolized to enalaprilat, which is formed by hydrolysis of its ethyl ester through hepatic metabolism. Enalaprilat is the active metabolite responsible for the therapeutic action 1–3. Therefore, the simultaneous detection of enalapril and enalaprilat in human plasma is of prime importance for pharmacokinetic studies.…”