Metabolism and pharmacokinetic study of deuterated osimertinib.

Osimertinib is a highly selective third-generation irreversible inhibitor of epidermal growth factor receptor mutant, which can be utilized to treat non-small cell lung cancer. As the substrate of cytochrome P450 enzyme, it is mainly metabolized by the CYP3A enzyme in humans. Among the metabolites produced by osimertinib, AZ5104, and AZ7550, which are demethylated that is most vital. Nowadays, deuteration is a new design approach for several drugs. This popular strategy is deemed to improve the pharmacokinetic characteristics of the original drugs. Therefore, in this study the metabolism profiles of osimertinib and its deuterated compound (osimertinib-d3) in liver microsomes and human recombinant cytochrome P450 isoenzymes and the pharmacokinetics in rats and humans were compared. After deuteration, its kinetic isotope effect greatly inhibited the metabolic pathway that produces AZ5104. The plasma concentration of the key metabolite AZ5104 of osimertinib-d3 in rats and humans decreased significantly compared with that of the osimertinib. This phenomenon was consistent with the results of the metabolism studies in vitro. In addition, the in vivo results indicated that osimertinib-d3 had higher systemic exposure (AUC) and peak concentration (Cmax ) compared with the osimertinib in rats and human body.

Progress and trends on the analysis of nucleic acid and its modification.

Nucleic acid is a collective term of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), and it is an essential substance in all known life forms. As numerous of studies have shown that nucleic acids can be used as therapeutic agents and the abnormality of various nucleic acid and its modification level has been proven to be closely bound up with changes in diseases such as cancer, the development of analytical methods for the nucleic acid and its modification has become one of the research hotspots in the field of life sciences. Compared with classical nucleic acid detection methods such as Northern blotting, Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (LC-MS/MS) and Polymerase Chain Reaction (PCR), novel analytical methods based on nanomaterials, nucleic acid amplification strategies and biosensors can better satisfy the needs for sensitivity and simplicity in current clinical diagnosis. Herein, the progress and trends of analysis of nucleic acid and its modification is discussed, aiming to provide guidance for the detection of nucleic acid and its modification in medical basic research and clinical diagnosis, treatment and prognosis.