Enantioselective determination of ( R )-zopiclone and ( S )-zopiclone (eszopiclone) in human hair by micropulverized extraction and chiral liquid chromatography/high resolution mass spectrometry

An overview of chiral separations of pharmaceutically active substances by HPLC (2018-2020)

This review provides a brief survey of chiral separation of pharmaceutically active substances published over the last 3 years (2018-2020). Chiral separation of drugs is an important area of research. The control of enantiomeric purity and determination of individual enantiomeric drug molecules is a necessity especially for clinical, analytical, and regulatory purposes. Among chromatographic resolution methods, high-performance liquid chromatography based on chiral stationary phases remains the most popular and effective method used for chiral separation of various drugs. In this review, attention is paid to several classes of chiral stationary phases that have been the most frequently used for drug enantioseparation during this period.

GRAPHIC ABSTRACT

Identification and characterization of new impurities in zopiclone tablets by LC-QTOF-MS

Zopiclone, a non-benzodiazepine hypnotic, is the first-line treatment for insomnia. The quality and stability of zopiclone tablets directly affects its efficacy and safety. However, the impurity investigation in zopiclone tablets remain incomplete. In this study, the accelerated and long-term stabilities of zopiclone tablets, as well as the stability characteristics under thermal and photolytic conditions were evaluated according to the ICH guidelines. In addition, a sensitive and specific LC-QTOF-MS method was developed for the separation and identification of all the impurities in zopiclone tablets and its stability test samples. Nine impurities were found in the test samples, five among them have not been reported before. Based on the accurate mass and elemental compositions of the parent and product ions obtained, the structures of all the detected impurities were identified. Combined with the formulation composition analysis and stability studies, the origins and the formation mechanisms of these impurities were elucidated. The obtained results are useful for the establishment of the optimum formulation, storage condition, manufacturing processes and quality control of zopiclone tablets.

Recent advances in chiral analysis for biosamples in clinical research and forensic toxicology

This article covers current methods and applications in chiral analysis from 2010 to 2020 for biosamples in clinical research and forensic toxicology. Sample preparation for aqueous and solid biological samples prior to instrumental analysis were discussed in the article. GC, HPLC, capillary electrophoresis and sub/supercritical fluid chromatography provide the efficient tools for chiral drug analysis coupled to fluorescence, UV and MS detectors. The application of chiral analysis is discussed in the article, which involves differentiation between clinical use and drug abuse, pharmacokinetic studies, pharmacology/toxicology evaluations and chiral inversion. Typical chiral analytes, including amphetamines and their analogs, anesthetics, psychotropic drugs, β-blockers and some other chiral compounds, are also reviewed.