The analysis of ramipril/ramiprilat concentration in human serum with liquid chromatography-tandem mass spectrometry – interpretation of high concentrations for the purposes of forensic toxicology

Ramipril is a popular angiotensin-converting enzyme inhibitor applied in the treatment of hypertension. Its therapeutic effect is oriented on the concentration of the active metabolite ramiprilat. The information about toxic drug levels is missing in the literature. Therefore, the aim of this work was an indication of possible toxic ranges based on the analysis of real samples with high ramiprilat concentrations. For these purposes, an appropriate analytical LC–MS/MS method was developed and validated according to forensic guidelines and applied in the routine. Most real samples targeted for ramipril/ramiprilat were associated with the typical therapeutic drug range of 1–40 ng/mL described in the literature. However, higher drug levels with ramiprilat concentrations above 100 ng/mL could also be observed infrequently in cases of driving under the influence of drugs or attempted suicides. To the best of the author’s knowledge, this is the first time antemortem ramipril and ramiprilat concentrations associated with driving under the influence of drugs and suicide attempts were discussed from a forensic point of view. The collected data enabled an indication of the ramiprilat toxic concentration range from about 600 ng/mL to at least 3500 ng/mL. The toxic concentration range discussed can be applied in the forensic practice as a reference for future cases.