Characterization of impurities in the bulk drug lisinopril by liquid chromatography/ion trap spectrometry

Abstract

Two trace impurities in the bulk drug lisinopril were detected by means of high-performance liquid chromatography coupled with mass spectrometry (HPLC/MS) with a simple and sensitive method suitable for HPLC/MS n analysis. The fragmentation behavior of lisinopril and the impurities was investigated, and two unknown impurities were elucidated as 2-(6-amino-1-(1-carboxyethylamino)-1-oxohexan-2-ylamino)-4-phenylbutanoic acid and 6-amino-2-(1-carboxy-3-phenylpropylamino)-hexanoic acid on the basis of the multi-stage mass spectrometry and exact mass evidence. The proposed structures of the two unknown impurities were further confirmed by nuclear magnetic resonance (NMR) experiments after preparative isolation.

Characterization of degradation products resulted from acidic hydrolysis of lisinopril under drastic conditions

“…System suitability of the validated method was accepted as described in Table 2. Studying the fragmentation pattern of lisinopril and its degradation products LC-MS/MS could identify the degradation products of lisinopril by studying its fragmentation patterns represented by the mass spectrum [14][15] . Table 4.…”

Synthesis and Characterization of Compounds Related to Lisinopril

“…This paper reports the synthesis and characterization of the unknown impurity (lysine analogue) along with three known impurities [ 6 – 18 ].…”

Study of the structures of photodegradation impurities and pathways of photodegradation of cilnidipine by liquid chromatography/Q‐Orbitrap mass spectrometry

“…In the full scan mode, the Q‐Orbitrap mass spectrometer can achieve compound identification and quantitation simultaneously with a great superiority in resolution and sensitivity . Structural identifications and analysis of the impurities in some 1,4‐dihydropyridine compounds using HPLC/MS n techniques have been reported; however, structural identification of the impurities in cilnidipine has not been officially reported. In this study, a LC/Q‐Orbitrap mass spectrometry technique was applied to study the structures of photodegradation impurities and photodegradation pathways of cilnidipine for the further improvement of official monographs in Pharmacopoeias.…”