Forced degradation profiling of Cilnidipine: A multi-technique characterization using UHPLC–MS, HRMS, Prep-HPLC and NMR

Abstract

Currently, no forced degradation studies for Cilnidipine are available. Therefore, it is essential to monitor its stability under various conditions. The main medical disorders that Cilnidipine is used to treat are hypertension, which is high blood pressure, and angina, also known as chest discomfort. Cilnidipine was exposed to forced degradation experiments, and the analysis of the samples was performed using liquid chromatography combined with mass spectrometry (LC–MS). According to the regulations, it was exposed to hydrolytic, oxidative, thermal, and photolytic degrading environments. The drug demonstrated stability under oxidative, thermal, and photolytic conditions, but it breaks down when exposed to acidic and basic conditions. The major deterioration, Impurity components formed during the forced degradation investigation, have been isolated to identify and quantify compounds.  In alkaline conditions, three degradation products (DP-1, DP-2, and DP-3) were generated, whereas acidic conditions yielded only one product (DP-4). A semi-preparative HPLC purification technique was used to isolate the identified degradation components. Characterization of the compounds was performed using high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR), including ¹H NMR, ¹³C NMR, heteronuclear single quantum coherence (HSQC), and heteronuclear multiple bond correlation (HMBC) spectroscopy.