Long-Term Stability of Benzodiazepines and Z-Hypnotic Drugs in Blood Samples Stored at Varying Temperatures

Abstract

Benzodiazepines (BZDs) and Z-drugs are among the most commonly prescribed pharmaceuticals in the world and are considered standard care for various mental illnesses and for treatment of sleeping and anxiety disorders, alcohol withdrawal, muscle spasms and epilepsy. Some BZDs are not allowed as pharmaceuticals in many countries, and they are used as “designer benzodiazepines” (DBZDs). All these compounds are typically screened in routine toxicological analyses for forensic purposes. Knowledge of time-dependent decreases in drug concentrations during storage or transport of samples is of considerable significance and allows forensic toxicologists to achieve reliable data, proper interpretation and high-quality results. The aim of this study was to evaluate changes in the amounts of selected BZDs, DBZDs and Z-drugs in blood samples stored at various temperatures. The study involved BZDs (19), DBZDs (3) and Z-drugs (2) spiked into blank blood. Subsequently, the blood samples were stored at various temperatures (room temperature, 4°C, -20°C and -80°C) for up to six months. Analyses were performed at 1–2 week intervals using liquid chromatography-tandem mass spectrometry (LC–MS/MS). The stability of compounds were evaluated under four temperature conditions over a 6 month. Some benzodiazepines were stable at all temperatures tested (e.g., diazepam, oxazepam, nordazepam, prazepam) and degradated of only 0-10%. The highest instability was observed for analyte samples kept at room temperature, and the losses in content for some compounds, e.g., lorazepam and chlordiazepoxide, were almost 100%. For other compounds, the stability was clearly different at each tested temperature. To the best of our knowledge, this is one of the first such comprehensive study of the long-term stability of benzodiazepines covering a wide range of different storage temperatures.

Relationship between clock gene expression and CYP2C19 and CYP3A4 with benzodiazepines

“…Benzodiazepines are among the most commonly prescribed drugs worldwide and are used to treat a variety of psychiatric, sleep, and anxiety disorders. 16,17 Benzodiazepine abuse and dependence are also global problems and are responsible for the majority of fatal overdose cases. 18,19 On the other hand, drug-metabolizing enzymes such as CYP3A4 and CYP2C19, are mainly involved in BZD metabolism.…”

Drug stability in forensic toxicology

“…The stability of zaleplon and zopiclone in fortified human blood, stored at À80 C, À20 C, 4 C, and room temperature for 6 months was examined by Banaszkiewicz et al (2022). Zaleplon was stable when stored at À80 and À20 C but lost 40% of analyte after 1 week when stored at room temperature and 4 C. Zopiclone concentrations were reduced by 50% after 10 days when stored at room temperature and were undetectable after 3 months.…”

“…The stability of zaleplon and zopiclone in fortified human blood, stored at −80°C, −20°C, 4°C, and room temperature for 6 months was examined by Banaszkiewicz et al (2022). Zaleplon was stable when stored at −80 and −20°C but lost 40% of analyte after 1 week when stored at room temperature and 4°C.…”