Chromatographic studies of unusual on-column degradation of cefaclor observed in the impurity separation by HPLC

Publication date: Available online 19 August 2019Source: Journal of Pharmaceutical and Biomedical AnalysisAuthor(s): Jia-Sheng Zhong, Yan-Huang, Jin-Zhi Wan, Xiao-Yang Yu, Ai-Ling Yu, Huan-Xiang Zeng, Zhen-Yang Chen, Xiang-Rong Zhou, Mei-DingAbstractAn unpredictable ghost peak was intermittently observed during the impurity separation of cefaclor and formulation by high performance liquid chromatography (HPLC) with contents below the reported threshold of approximately 0.3% in different laboratories. Through a series of investigations, the ghost peak was identified as an unusual on-column degradant of cefaclor formed under elevated column temperature but was not an actual sample impurity. The chemical structure of the degradant was determined by spectroscopic methods, including high resolution mass spectrometry (HRMS) and 1H-NMR. Consequently, the unknown peak was identified as a C-4 oxidative decarboxylation analog of cefaclor. The formation mechanism of the analog is proposed, and it is suggested that elevated column temperature during HPLC analysis has a profound effect on the degradation. Dissolved oxygen in the mobile phase may promote the formation of the ghost peak. The degradation can be suppressed by using a column temperature below 30 °C. Moreover, several other prevention measures are suggested based upon the results of the investigation.Graphical Abstract
Source: Journal of Pharmaceutical and Biomedical Analysis - Category: Drugs & Pharmacology Source Type: research