Investigation of the Oxidative Degradation Pathway of Amidoximes by LC/MS/MS

Samir, Ebtihal; Mamdouh, Mamdouh F. A; M Derayea, Sayed M

doi:10.21608/ejchem.2020.50067.3024

Investigation of the Oxidative Degradation Pathway of Amidoximes by LC/MS/MS

Document Type : Original Article

Authors

¹ Department of Analytical Chemistry, Faculty of Pharmacy, Deraya University, New-Minia, 61519-Minia, Egypt

² Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Sohag University, 82524 Sohag, Egypt

³ Department of Analytical Chemistry, Faculty of Pharmacy, Minia University, 61519-Minia, Egypt

10.21608/ejchem.2020.50067.3024

Abstract

The oxidative degradation pathway for a newly prepared amidoxime prodrug has been studied using LC/MS/MS. The amidoxime was subjected to oxidation with K3Fe(CN)6/NaOH for different time periods and at different temperatures. The chromatographic separation was performed on RP amide column and 0.1% aqueous formic acid; acetonitrile containing 0.1% formic acid (50:50 v/v) as a mobile phase. The elution in Ultra-performance liquid chromatography (UPLC) was carried out in the isocratic mode. The normal LC/MS/MS showed that the cleavage occurs through amidoxime ester. At room temperature, no important oxidation products were obtained. However, upon heating the parent amidoxime was disappeared with the concomitant appearance of a new compound which is the most stable peak (base peak) at m/z = 333.80. The formed degradation product was suggested to be the disodium salt of benzaldoxime peroxide. These results give indication about the mechanism of release of nitric oxide from amidoxime and ensure that amidoximes are important nitric oxide donors.

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