A comprehensive study on rearrangement reactions in collision-induced dissociation mass spectrometric fragmentation of protonated diphenyl and phenyl pyridyl ethers.

Rationale: Recently, we have reported a forced degradation study of a pharmaceutical drug regorafenib which contains a phenyl pyridyl ether derivative as building block. We observed interesting rearrangements in two of its degradation products in tandem mass spectrometry (MS/MS) experiments. As diphenyl ether derivatives are also molecular building blocks of biological importance and used as herbicides and flame retardants, we decided to investigate specifically the fragmentation behavior of these compounds along with phenyl pyridyl derivatives in detail using high-resolution electrospray ionization (ESI) MS/MS.

Identification and structural characterization of hydrolytic degradation products of alvimopan by LC/QTOF/MS/MS and NMR studies.

Alvimopan (ALV), a peripherally acting mu-opioid receptor (PAM-OR) antagonist used for the treatment of postoperative ileus, was examined for its degradation behaviour under different stress conditions. A total of five degradation products (DP1-DP5) were formed and identified using high-performance liquid chromatography (HPLC) method. Primarily, complete fragmentation pathways of the protonated drug and its degradation products (DP1-DP5) were elucidated by using liquid chromatography-mass spectrometry (LC/MS) and high-resolution mass spectrometry (HRMS) studies.

LC/QTOF/MS/MS characterization, molecular docking and in silico toxicity prediction studies on degradation products of anagliptin.

Pharmaceutical drugs are potential molecules with specific biological activity. However, long-term use of these chemical molecules can affect the human physiological system because of their increased levels in the human body. Therefore, identification and structure elucidation of impurities or degradation products should be taken into consideration in order to assure drug safety.

First report on the pharmacokinetic profile of nimbolide, a novel anticancer agent in oral and intravenous administrated rats by LC/MS method.

Nimbolide is a novel, natural compound with promising potential as a drug candidate for anticancer activity. It is isolated from the Indian traditional medicinal plant Azadirachta indica popularly known as neem. The present study was undertaken to explore the oral bioavailability and pharmacokinetic characteristics of nimbolide in rats using the LC/QTOF/MS method.

Characterization of forced degradation products of canagliflozine by liquid chromatography/quadrupole time-of-flight tandem mass spectrometry and in silico toxicity predictions.

Rationale: Forced degradation studies are useful for better understanding of the stability of active pharmaceutical ingredients and drugs and to generate information about drug degradation pathways and formation of degradation products (DPs). Identification of DPs plays a vital role in establishing the safety and therapeutic benefit of a drug.

Methods: Canagliflozin (CAN) was subjected to different stress conditions as per International Conference on Harmonization guidelines (Q1A R2).