Separation and structure determination of nicardipine photoproducts by LC‐ESI‐MS

Abstract

A sample of 0.104 M nicardipine in methanol was photoirradiated with a Philips 400 W UV lamp for 3 h in a photochemical chamber. A total of four major photoproducts were found from the HPLC chromatogram. The same sample was used for taking LC-MS, while eight major photoproducts were observed and the structures elucidated by analyzing the CID patterns of their respective mass spectra. A reaction scheme of nicardipine is proposed that the photochemical reactions occur mainly via oxidation of 1,4-dihydropyridine moiety, following the stepwise photo-reduction of the m-nitro group and demethylation of the ester group at 5-position of the pyridine ring.

Characterization of two new potential impurities of Valsartan obtained under photodegradation stress condition

“…Generation, detection and isolation of impurities DP-1 and DP-2 VAL was stressed by exposure to radiation from a metal halide lamp, a light source that has been widely used in drug photostability research [24]. Its output spectrum is continuous from 315 to 2000 nm, being uniform in the 350-650 nm region and closely resembles that of sunlight [17,25].…”

Resonance Rayleigh scattering and resonance nonlinear scattering methods for the determination of nicardipine hydrochloride using eosin Y as a probe

“…Therefore, an analytical method must be as rapid as possible and based on a low number of steps. 23 The proposed method just need to mix NCD and EY in suitable buffer solution, and the reaction could complete in 5 min at room temperature. So the RRS method could completely meet the requirement of simple and fast for the determination of NCD.…”