Chemical Communications

Gauging circadian variation in ketamine metabolism by real-time breath analysis

Gauging circadian variation in ketamine metabolism by real-time breath analysis

P. M-L Sinues, M. Kohler, S. A. Brown, R. Zenobi and R. Dallmann

The time-of-day of drug application is an important factor in maximizing efficacy and minimizing toxicity. Real-time in vivo mass spectrometric breath analysis and research of mice was deployed to investigate time-of-day variation in ketamine metabolism. Different production rates of ketamine metabolites were found in opposite circadian phases.

SESI-HRMS reveals tryptophan pathway metabolites in exhaled human breath

SESI-HRMS reveals tryptophan pathway metabolites in exhaled human breath

D. García-Gómez, T. Gaisl, L. Bregy, P. M-L Sinues, M. Kohler and R. Zenobi

Disorders in tryptophan metabolism result in diseases such as vitamin B6 responsive xanthurenic aciduria, hydroxy-kynureninuria, tryptophanuria and Hartnup disease. The authors hypotesized that breath analysis may reveal compounds that are metabolically linked to tryptophan. The mass range of detected metabolites reached up to 265 u, which is beyond the mass range limit (150–200 u) of competing breath research techniques such as PTR or SIFT-MS.