Preliminary communication

Separation, Identification and Structural Elucidation of a New Impurity in the Drug Substance of Amlodipine Maleate Using LC-MS/MS, NMR and IR

Gosula Venkat Ram Reddy ; Department of Chemistry, Sri Krishnadevaraya University, Anantapur 534-729, India
Avvaru Praveen Kumar ; Department of Chemistry, Yeungnam University, 214-1 Dae-dong, Gyeongsan 712-749, Korea
Bobba Venkateswara Reddy ; Department of Chemistry, Sri Krishnadevaraya University, Anantapur 534-729, India
Jadi Sreeramulu ; Department of Chemistry, Sri Krishnadevaraya University, Anantapur 534-729, India
Jung Hag Park ; Department of Chemistry, Yeungnam University, 214-1 Dae-dong, Gyeongsan 712-749, Korea

Abstract

Amlodipine maleate is a maleate salt of 3-ethyl 5-methyl 2-[(2-aminoethoxy)methyl]-4-(2-
chlorophenyl)-6-methyl-1,4-dihydropyridine-3,5-dicarboxylate. An unknown impurity at m/ z 392.2 for
[M+H]+ ion has been detected during the accelerated stability analysis (40 °C /75 % RH) of amlodipine
maleate drug substance by reverse-phase high performance liquid chromatography–mass spectrometry
(RP-HPLC-MS). MS and MS/MS spectra of amlodipine maleate and unknown impurity are obtained using
HPLC-MS/MS equipped with positive electrospray ionization (ESI). The nuclear magnetic resonance
(NMR) and infrared (IR) spectra of the unknown impurity are recorded after isolation of the impurity by
preparative HPLC. Based on MS, NMR and IR spectral data, the structure of the unknown impurity was
proposed as 5-ethyl-7-methyl-6-(2-chlorophenyl)-8-methyl-3,4,6,7-tetrahydro-2H-1,4-benzoxazine-5,7-
dicarboxylate.

Keywords

amlodipine maleate; new impurity; separation and identification; structural elucidation; HPLCMS/MS; NMR and IR studies

Hrčak ID:

62650

URI

https://hrcak.srce.hr/62650

Publication date:

1.12.2010.

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