Liquid chromatography-high resolution-tandem mass spectrometry using Orbitrap technology for comprehensive screening to detect drugs and their metabolites in blood plasma.

Orbitrap technology was successfully applied for broad metabolite-based LC-high resolution (HR)-MS screening of drugs in clinical and forensic toxicology. This paper aims to elucidate whether this technology can also be used for a corresponding blood plasma screening after simple precipitation without or with consecutive on-line extraction using turbulent flow chromatography (TurboFlow). The analytes were separated within 10 min and detected by a Q-Exactive mass spectrometer in full scan mode after positive/negative switching. In one single run, a target screening for about 700 relevant compounds was developed in parallel with data-dependent acquisition for unknowns. A compound was positively identified when the corresponding accurate mass precursor ion and the five most intense fragment ions were detected and the MS/MS spectrum fits well with the corresponding full HR-MS/MS reference library currently containing over 2000 parent drugs and 2500 metabolites. All over all run times were 17 min for precipitation and 21 min for TurboFlow after precipitation. Method validation was successfully performed for representative drugs and metabolites concerning recovery, matrix effect, process efficiency, and limits of detection and identification. Process efficiency data ranged for most analytes from 3 to 138% with coefficients of variation (CV) ≤ 20% for precipitation and from 1 to 156% with CV ≤ 20% for TurboFlow. Applicability studies showed that the developed method provided fast, simple, and robust screening and identification of a broad range of drugs within therapeutic ranges.

Metabolic patterns of JWH-210, RCS-4, and THC in pig urine elucidated using LC-HR-MS/MS: Do they reflect patterns in humans?

The knowledge of pharmacokinetic (PK) properties of synthetic cannabinoids (SCs) is important for interpretation of analytical results found for example in intoxicated individuals. In the absence of human data from controlled studies, animal models elucidating SC PK have to be established. Pigs providing large biofluid sample volumes were tested for prediction of human PK data. In this context, the metabolic fate of two model SCs, namely 4-ethylnaphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-210) and 2-(4-methoxyphenyl)-1-(1-pentyl-indol-3-yl)methanone (RCS-4), was elucidated in addition to Δ9 -tetrahydrocannabinol (THC). After intravenous administration of the compounds, hourly collected pig urine was analyzed by liquid chromatography-high resolution mass spectrometry. The following pathways were observed: for JWH-210, hydroxylation at the ethyl side chain or pentyl chain and combinations of them followed by glucuronidation; for RCS-4, hydroxylation at the methoxyphenyl moiety or pentyl chain followed by glucuronidation as well as O-demethylation followed by glucuronidation or sulfation; for THC, THC glucuronidation, 11-hydroxylation, followed by carboxylation and glucuronidation. For both SCs, parent compounds could not be detected in urine in contrast to THC. These results were consistent with those obtained from human hepatocyte and/or human case studies. Urinary markers for the consumption of JWH-210 were the glucuronide of the N-hydroxypentyl metabolite (detectable for 3-4 h) and of RCS-4 the glucuronides of the N-hydroxypentyl, hydroxy-methoxyphenyl (detectable for at least 6 h), and the O-demethyl-hydroxy metabolites (detectable for 4 h). Copyright © 2016 John Wiley & Sons, Ltd.

LC-HR-MS/MS standard urine screening approach: Pros and cons of automated on-line extraction by turbulent flow chromatography versus dilute-and-shoot and comparison with established urine precipitation.

Comprehensive urine screening for drugs and metabolites by LC-HR-MS/MS using Orbitrap technology has been described with precipitation as simple workup. In order to fasten, automate, and/or simplify the workup, on-line extraction by turbulent flow chromatography and a dilute-and-shoot approach were developed and compared. After chromatographic separation within 10min, the Q-Exactive mass spectrometer was run in full scan mode with positive/negative switching and subsequent data dependent acquisition mode. The workup approaches were validated concerning selectivity, recovery, matrix effects, process efficiency, and limits of identification and detection for typical drug representatives and metabolites. The total workup time for on-line extraction was 6min, for the dilution approach 3min. For comparison, the established urine precipitation and evaporation lasted 10min. The validation results were acceptable. The limits for on-line extraction were comparable with those described for precipitation, but lower than for dilution. Thanks to the high sensitivity of the LC-HR-MS/MS system, all three workup approaches were sufficient for comprehensive urine screening and allowed fast, reliable, and reproducible detection of cardiovascular drugs, drugs of abuse, and other CNS acting drugs after common doses.

The effect of renal denervation in moderate treatment-resistant hypertension with confirmed medication adherence.

OBJECTIVES: Data on the blood pressure (BP)-lowering effect of renal denervation (RDN) in moderate treatment-resistant hypertension (TRH) are limited. Moreover, change of adherence to medication, as one potential confounder of BP response, has never been analyzed rigorously in this group of patients. We analyzed the effect of RDN on BP in patients with moderate TRH who were retrospectively found to be completely adherent to their antihypertensive medication. METHODS: Our study cohort comprised 40 patients with moderate TRH [office BP ≥ 140/90 but <160/100 mmHg and 24-h ambulatory BP monitoring (ABPM) ≥130/80 mmHg] who underwent catheter-based RDN. Further major inclusion criterion was complete adherence to their medication (≥80% intake of their prescribed antihypertensive drugs) at baseline (assessed by retrospective toxicological analysis). RESULTS: Six months after RDN, office BP was reduced by -10/-6 mmHg (SBP: 149 ±â€Š6 vs. 139 ±â€Š15 mmHg; DBP: 81 ±â€Š12 vs. 75 ±â€Š10 mmHg; both P < 0.001) and 24-h ABPM by -7/-4 mmHg (SBP: 150 ±â€Š14 vs. 143 ±â€Š16 mmHg, P = 0.005; DBP: 82 ±â€Š10 vs. 78 ±â€Š9 mmHg, P = 0.009). Number of prescribed antihypertensive medication [6.0 (5.0-6.0) vs. 5.5 (5.0-6.0), P = 0.013] and adherence rate (95.2 ±â€Š7.6 vs. 91.7 ±â€Š13.9%, P = 0.065) was slightly reduced 6 months after RDN, both likely to underestimate the true BP reduction. CONCLUSION: Thus, our data indicate that even after given full respect to drug adherence as potential confounder of BP response after RDN, both office and 24-h ABPM were substantially reduced in patients with moderate TRH.

Blood pressure changes after catheter-based renal denervation are related to reductions in total peripheral resistance.

BACKGROUND: Renal denervation (RDN) can reduce sympathetic activity and blood pressure (BP) in patients with uncontrolled hypertension. The exact mechanisms by which RDN results in BP reductions are yet not fully established. METHODS AND RESULTS: This study investigated the effects of RDN on office BP, 24-h ambulatory BP, noninvasive 10-min beat-to-beat digital pulse wave analysis, total peripheral resistance (TPR), cardiac output, and plasma renin and aldosterone serum concentrations in 30 patients with resistant hypertension. Adherence to antihypertensive drugs was assessed by liquid chromatography high-resolution tandem mass spectrometry analysis in plasma and urine at baseline and at 6 month. RDN significantly reduced office BP, beat-to-beat BP, and 24-h ambulatory BP by 19/6 (P = 0.021/P = 0.012), 12/7 (P = 0.005/P = 0.005), and 10/5  mmHg (P = 0.001/P = 0.049) at 6 months, respectively. TPR decreased from 1696 to 1377  dyn × s/cm (-19%; P = 0.027). This reduction was not associated with significant changes in cardiac output. The changes in office, ambulatory, and beat-to-beat BP correlated with the reductions of TPR. Adherence to antihypertensive treatment remained unchanged during the study period (84.7% at baseline, 83.6% at 6 months, P = 0.782). CONCLUSION: RDN reduced office BP, beat-to-beat BP, and 24-h ambulatory BP in patients with resistant hypertension after 6 months. The BP changes were associated with reductions in peripheral resistance, whereas cardiac output, plasma renin, and aldosterone levels remained unchanged. The observed effects were not explained by an increased intake of antihypertensive medications.

Orbitrap technology for comprehensive metabolite-based liquid chromatographic-high resolution-tandem mass spectrometric urine drug screening - exemplified for cardiovascular drugs.

LC-high resolution (HR)-MS well established in proteomics has become more and more important in bioanalysis of small molecules over the last few years. Its high selectivity and specificity provide best prerequisites for its use in broad screening approaches. Therefore, Orbitrap technology was tested for developing a general metabolite-based LC-HR-MS/MS screening approach for urinalysis of drugs necessary in clinical and forensic toxicology. After simple urine precipitation, the drugs and their metabolites were separated within 10 min and detected by a Q-Exactive mass spectrometer in full scan with positive/negative switching, and subsequent data dependent acquisition (DDA) mode. Identification criteria were the presence of accurate precursor ions, isotopic patterns, five most intense fragment ions, and comparison with full HR-MS/MS library spectra. The current library contains over 1900 parent drugs and 1200 metabolites. The method was validated for typical drug representatives and metabolites concerning recovery, matrix effects, process efficiency, and limits showed acceptable results. The applicability was tested first for cardiovascular drugs, which should be screened for in poisoning cases and for medication adherence of hypertension patients. The novel LC-HR-MS/MS method allowed fast, simple, and robust urine screening, particularly for cardiovascular drugs showing the usefulness of Orbitrap technology for drug testing.

Blood pressure reductions following catheter-based renal denervation are not related to improvements in adherence to antihypertensive drugs measured by urine/plasma toxicological analysis.

Renal denervation can reduce blood pressure in patients with uncontrolled hypertension. The adherence to prescribed antihypertensive medication following renal denervation is unknown. This study investigated adherence to prescribed antihypertensive treatment by liquid chromatography-high resolution tandem mass spectrometry in plasma and urine at baseline and 6 months after renal denervation in 100 patients with resistant hypertension, defined as baseline office systolic blood pressure ≥140 mmHg despite treatment with ≥3 antihypertensive agents. At baseline, complete adherence to all prescribed antihypertensive agents was observed in 52 patients, 46 patients were partially adherent, and two patients were completely non-adherent. Baseline office blood pressure was 167/88 ± 19/16 mmHg with a corresponding 24-h blood pressure of 154/86 ± 15/13 mmHg. Renal denervation significantly reduced office and ambulatory blood pressure at 6-month follow-up by 15/5 mmHg (p < 0.001/p < 0.001) and 8/4 mmHg (p < 0.001/p = 0.001), respectively. Mean adherence to prescribed treatment was significantly reduced from 85.0 % at baseline to 80.7 %, 6 months after renal denervation (p = 0.005). The blood pressure decrease was not explained by improvements in adherence following the procedure. Patients not responding to treatment significantly reduced their drug intake following the procedure. Adherence was highest for angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and beta blockers (>90 %) and lowest for vasodilators (21 %). In conclusion, renal denervation can reduce office and ambulatory blood pressure in patients with resistant hypertension despite a significant reduction in adherence to antihypertensive treatment after 6 months.

Metabolism of the new psychoactive substances N,N-diallyltryptamine (DALT) and 5-methoxy-DALT and their detectability in urine by GC-MS, LC-MSn, and LC-HR-MS-MS.

N,N-Diallyltryptamine (DALT) and 5-methoxy-DALT (5-MeO-DALT) are synthetic tryptamine derivatives commonly referred to as so-called new psychoactive substances (NPS). They have psychoactive effects that may be similar to those of other tryptamine derivatives. The objectives of this work were to study the metabolic fate and detectability, in urine, of DALT and 5-MeO-DALT. For metabolism studies, rat urine obtained after high-dose administration was prepared by precipitation and analyzed by liquid chromatography-high-resolution mass spectrometry (LC-HR-MS-MS). On the basis of the metabolites identified, several aromatic and aliphatic hydroxylations, N-dealkylation, N-oxidation, and combinations thereof are proposed as the main metabolic pathways for both compounds. O-Demethylation of 5-MeO-DALT was also observed, in addition to extensive glucuronidation or sulfation of both compounds after phase I transformation. The cytochrome P450 (CYP) isoenzymes predominantly involved in DALT metabolism were CYP2C19, CYP2D6, and CYP3A4; those mainly involved in 5-MeO-DALT metabolism were CYP1A2, CYP2C19, CYP2D6, and CYP3A4. For detectability studies, rat urine was screened by GC-MS, LC-MS(n), and LC-HR-MS-MS after administration of low doses. LC-MS(n) and LC-HR-MS-MS were deemed suitable for monitoring consumption of both compounds. The most abundant targets were a ring hydroxy metabolite of DALT, the N,O-bis-dealkyl metabolite of 5-MeO-DALT, and their glucuronides. GC-MS enabled screening of DALT by use of its main metabolites only.

Studies on the metabolism and toxicological detection of the new psychoactive designer drug 2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine (25I-NBOMe) in human and rat urine using GC-MS, LC-MS(n), and LC-HR-MS/MS.

25I-NBOMe, a new psychoactive substance, is a potent 5-HT2A receptor agonist with strong hallucinogenic potential. Recently, it was involved in several fatal and non-fatal intoxication cases. The aim of the present work was to study its phase I and II metabolism and its detectability in urine screening approaches. After application of 25I-NBOMe to male Wistar rats, urine was collected over 24 h. The phase I and II metabolites were identified by LC-HR-MS/MS in urine after suitable workup. For the detectability studies, standard urine screening approaches (SUSA) by GC-MS, LC-MS(n), and LC-HR-MS/MS were applied to rat and also to authentic human urine samples submitted for toxicological analysis. Finally, an initial CYP activity screening was performed to identify CYP isoenzymes involved in the major metabolic steps. 25I-NBOMe was mainly metabolized by O-demethylation, O,O-bis-demethylation, hydroxylation, and combinations of these reactions as well as by glucuronidation and sulfation of the main phase I metabolites. All in all, 68 metabolites could be identified. Intake of 25I-NBOMe was detectable mainly via its metabolites by both LC-MS approaches, but not by the GC-MS SUSA. Initial CYP activity screening revealed the involvement of CYP1A2 and CYP3A4 in hydroxylation and CYP2C9 and CYP2C19 in O-demethylation. The presented study demonstrated that 25I-NBOMe was extensively metabolized and could be detected only by the LC-MS screening approaches. Since CYP2C9 and CYP3A4 are involved in initial metabolic steps, drug-drug interactions might occur in certain constellations.

Elucidation of the metabolites of the novel psychoactive substance 4-methyl-N-ethyl-cathinone (4-MEC) in human urine and pooled liver microsomes by GC-MS and LC-HR-MS/MS techniques and of its detectability by GC-MS or LC-MS(n) standard screening approaches.

4-methyl-N-ethcathinone (4-MEC), the N-ethyl homologue of mephedrone, is a novel psychoactive substance of the beta-keto amphetamine (cathinone) group. The aim of the present work was to study the phase I and phase II metabolism of 4-MEC in human urine as well as in pooled human liver microsome (pHLM) incubations. The urine samples were worked up with and without enzymatic cleavage, the pHLM incubations by simple deproteinization. The metabolites were separated and identified by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-high resolution-tandem mass spectrometry (LC-HR-MS/MS). Based on the metabolites identified in urine and/or pHLM, the following metabolic pathways could be proposed: reduction of the keto group, N-deethylation, hydroxylation of the 4-methyl group followed by further oxidation to the corresponding 4-carboxy metabolite, and combinations of these steps. Glucuronidation could only be observed for the hydroxy metabolite. These pathways were similar to those described for the N-methyl homologue mephedrone and other related drugs. In pHLM, all phase I metabolites with the exception of the N-deethyl-dihydro isomers and the 4-carboxy-dihydro metabolite could be confirmed. Glucuronides could not be formed under the applied conditions. Although the taken dose was not clear, an intake of 4-MEC should be detectable in urine by the GC-MS and LC-MS(n) standard urine screening approaches at least after overdose.

Current position of high-resolution MS for drug quantification in clinical & forensic toxicology.

This paper reviews high-resolution MS approaches published from January 2011 until March 2014 for the quantification of drugs (of abuse) and/or their metabolites in biosamples using LC-MS with time-of-flight or Orbitrap™ mass analyzers. Corresponding approaches are discussed including sample preparation and mass spectral settings. The advantages and limitations of high-resolution MS for drug quantification, as well as the demand for a certain resolution or a specific mass accuracy are also explored.

Direct analysis of the mushroom poisons α- and ß-amanitin in human urine using a novel on-line turbulent flow chromatography mode coupled to liquid chromatography-high resolution-mass spectrometry/mass spectrometry.

Poisonings with Amanita phalloides toxins require fast diagnosis in order to avoid expensive and unnecessary therapies. Initial clinical assessment in combination with urinary amanitin analysis is necessary for a definite diagnosis. Therefore, a simple, fast, and robust method was developed for reliable detection of α- and ß-amanitin as well as for fully validated quantification of α-amanitin in human urine. After simple dilution and centrifugation of the urine sample, a fast on-line extraction using a Transcend TLX-II system based on turbulent flow chromatography (TurboFlow) was established. A new TurboFlow mode was introduced, the pseudo quick elute mode (PQEM), which had more options for method optimization than the generic quick elute mode (QEM). It allowed running several modes in one valve arrangement. The PQEM showed better practicability in routine and emergency analysis than the previously used methods. After extraction, the fast 15min LC-high resolution (HR)-MS/MS analysis allowed reliable identification of α- and ß-amanitin based on fragments identified using so-called HR pseudo MS(3) experiments. According to international recommendations, the requirements for full validation including the parameters selectivity, calibration, accuracy, precision, recovery, matrix effects, and stability were fulfilled for α-amanitin. The method was successfully applied to the analysis of authentic urine samples containing amatoxins. In conclusion, this method allowed the determination of amatoxins using the novel PQEM in a faster, robust, and more reliable way than existing methods, making it suitable for daily routine and especially emergency toxicological analysis.