Simultaneous time-course measurements of metoprolol and α-hydroxyl metoprolol in fingermarks after oral administration by liquid chromatography tandem mass spectrometry

Abstract

The aim of this study was to evaluate whether fingerprints are suitable to be applied as the biometric identification samples by testing the orally administered drugs needs to be taken daily. The dosage of BETALOC® was administered to subjects following single and multiple doses and its active ingredient metoprolol and its main metabolite α-hydroxyl metoprolol were selected as the analytes. The subjects washed their hands and pressed fingertips onto glass slides at fixed sampling points (from 1 h to 7 days), and the analytes were extracted using cotton swabs 30 times followed by ultrasonic assistance in 30℃ methanol solution for 5 min with working power of 2000 W after optimization. The drugs in blood were taken from their elbow vein and deproteinized before analysis. Analysis were performed using liquid chromatography–tandem mass spectrometry (LC/MS/MS), and their concentration time course in fingerprints and blood were evaluated and compared. Results showed that metoprolol was detected 1 h after ingestion both in fingerprints and blood, while α-hydroxyl metoprolol was detected from sampling points of 2 h in fingerprint and 3 h in blood, respectively. Drugs could be detected for longer periods in blood than in fingerprint in single dose administration. However, in multiple doses, they could reach a steady detectable state in fingerprints from the fifth day after oral administration, and could serve as a more rapid and simpler alternative for drug analysis. We demonstrate that fingerprints could be applied as the biometric identification samples for orally administered drugs in multiple-doses, and could be applied to drug testing in criminal investigations.