Development of the first metabolite-based LC-MS n urine drug screening procedure-exemplified for antidepressants

Abstract

In contrast to GC-MS libraries, currently available LC-MS libraries for toxicological detection contain besides parent drugs only some main metabolites limiting their applicability for urine screening. Therefore, a metabolite-based LC-MS(n) screening procedure was developed and exemplified for antidepressants. The library was built up with MS(2) and MS(3) wideband spectra using an LXQ linear ion trap with electrospray ionization in the positive mode and full-scan information-dependent acquisition. Pure substance spectra were recorded in methanolic solution and metabolite spectra in urine from rats after administration of the corresponding drugs. After identification, the metabolite spectra were added to the library. Various drugs and metabolites could be sufficiently separated. Recovery, process efficiency, matrix effects, and limits of detection for selected drugs were determined using protein precipitation. Automatic data evaluation was performed using ToxID and SmileMS software. The library consists of over 700 parent compounds including 45 antidepressants, over 1,600 metabolites, and artifacts. Protein precipitation led to sufficient results for sample preparation. ToxID and SmileMS were both suitable for target screening with some pros and cons. In our study, only SmileMS was suitable for untargeted screening being not limited to precursor selection. The LC-MS(n) method was suitable for urine screening as exemplified for antidepressants. It also allowed detecting unknown compounds based on known fragment structures. As ion suppression can never be excluded, it is advantageous to have several targets per drug. Furthermore, the detection of metabolites confirms the body passage. The presented LC-MS(n) method complements established GC-MS or LC-MS procedures in the authors' lab.

Metabolic fate of desomorphine elucidated using rat urine, pooled human liver preparations, and human hepatocyte cultures as well as its detectability using standard urine screening approaches

“…The acidic and neutral compounds (eluate A) were eluted with 1 mL of methanol into a 1.5-mL reaction vial and the basic compounds (eluate B) with 1 mL of a freshly prepared mixture of methanol/aqueous ammonia 32 % (98:2, v/v). Only eluate B was evaporated to dryness under a stream of nitrogen and reconstituted with 50 μL of a mixture of eluent Sample preparation for the identification of the phase II metabolites was carried out according to a published method [12,13]. A volume of 100 μL of urine was mixed with 500 μL of acetonitrile for precipitation.…”

“…Urine was precipitated for both liquid chromatography-mass spectrometry (LC-MS) approaches [8,9,12]. The data of LC-MS n were evaluated using TF ToxID and library search [8,12,21] and of LC-HR-MS/MS using TF TraceFinder [9] and library search …”

“…In addition, HepG2 and HepaRG cell lines should be tested as new tools for the prediction of human hepatic metabolism of drugs of abuse. Finally, the detectability of desomorphine and its metabolites by common SUSAs [9][10][11][12] should be investigated.…”

Descripción del doping en el equino y evaluación en Chile.

“…Estas fases son denominadas procesos de biotransformación ya que la sustancia transforma su estructura química mediante reacciones enzimáticas, el resultado de este proceso culmina en el aumento de la hidrofilidad de las drogas y la disminución de su toxicidad. Por otra parte, estas reacciones de biotransformación pueden provocar la bioactivación de fármacos en cuyo caso el metabolito es más toxico y/o más activo que el fármaco original (Wissenbach, 2012).…”

Determination of 13 Organic Toxicants in Human Blood by Liquid-Liquid Extraction Coupling High-Performance Liquid Chromatography Tandem Mass Spectrometry

“…[5][6][7][8][9][10] ATDs, as the first choice in the treatment of depressive illness, are becoming increasingly used due to the rapid growth in population of depression-affected people worldwide. [11][12][13][14] Meanwhile, the abuse of ATDs has become a significant problem in societies across the world because of their easy availability and toxicological effect. [15][16][17][18][19] Over the past decades, forensic cases related to ATDs abuse was quite common, such as driving under the influence of drugs, violent crime, drug-facilitated sexual assault and other cases of sudden or violent deaths.…”