Investigations into the stability of 17 psychoactive drugs in a “simulated postmortem blood” model

In the postmortem environment, some drugs and metabolites may degrade due to microbial activity, even forming degradation products that are not produced in humans. Consequently, underestimation or overestimation of perimortem drug concentrations or even false negatives are possible when analyzing postmortem specimens. Therefore, understanding whether medications may be susceptible to microbial degradation is critical in order to ensure that reliable detection and quantitation of drugs and their degradation products is achieved in toxicology screening methods. In this study, a “simulated postmortem blood” model constructed of antemortem human whole blood inoculated with a broad population of human fecal microorganisms was used to investigate the stability of 17 antidepressant and antipsychotic drugs. Microbial communities present in the experiments were determined to be relevant to postmortem blood microorganisms by 16S rRNA sequencing analyses. After 7 days of exposure to the community at 37°C, drug stability was evaluated using liquid chromatography coupled with diode array detection (LC-DAD) and with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Most of the investigated drugs were found to be stable in inoculated samples and noninoculated controls. However, the 1,2-benzisothiazole antipsychotics, ziprasidone and lurasidone, were found to degrade at a rate comparable with the known labile control, risperidone. In longer experiments (7 to 12 months), where specimens were stored at −20°C, 4°C, and ambient temperature, N-dealkylation degradation products were detected for many of the drugs, with greater formation in specimens stored at −20°C than at 4°C.     

In vitro degradation of ziprasidone in human whole blood

A systematic study was performed into the degradation of ziprasidone in simulated postmortem blood. Fifteen potential degradation products not previously reported in the literature were observed. Four resulted from degradation in human blood, whereas the remaining products resulted from reaction with solvents: four from alkaline degradation, four from reaction with acetaldehyde, and three from reaction with acetone. To identify possible degradation products, a liquid chromatograph-diode array detector (LC-DAD) and liquid chromatograph quadrupole-time-of-flight mass spectrometer (LC-QTOF-MS) operating in auto-MS/MS mode were used. It was indicated from red-shifted UV–Vis spectra, accurate mass data, mass fragmentation data, and a deuteration experiment that the site of ziprasidone degradation, in the in vitro blood experiments, was the methylene carbon of the oxindole moiety. The major in vitro blood degradation products were proposed to be E/Z isomers of 3-ethylidene-ziprasidone. Further, another in vitro degradation product in microbially inoculated blood specimens was proposed to be 3-ethyl-ziprasidone. 3-Ethylidene-ziprasidone was hypothesized to form from the reaction of ziprasidone with acetaldehyde derived from the ethanol used to spike ziprasidone into the in vitro blood experiments. Data from two postmortem investigations were available for retrospective reanalysis. Attempts were made to detect degradation products of ziprasidone, but none were found.     

Identification and characterization of major degradation products of risperidone in bulk drug and pharmaceutical dosage forms

Acid, base and oxygen stability of risperidone, a novel anti-psychotic drug, has been evaluated storing the sample in solution phase. One of the major degradation products has been identified and characterized by using techniques namely IR, MS and NMR after isolation by preparative LC. The other major degradation product has been identified with help of MS/MS data and by co-eluting in analytical LC with the available standard. The effect of acid and base resulted in the formation of hydroxy risperidone and the effect of oxygen lead to the formation of N-oxide of risperidone. The two major degradation products in the dosage forms were also characterized as 9-hydroxy risperidone and N-oxide of risperidone, after enrichment through preparative LC, by LC-MS/MS and HPLC. Structural elucidation of degradation product leading to the formation of N-oxide of risperidone is discussed in detail.     

Stability of morphine, morphine-3-glucuronide, and morphine-6-glucuronide in fresh blood and plasma and postmortem blood samples

The present study was designed to determine the stability of morphine and its glucuronides in spiked fresh blood and plasma from live individuals as well as in four authentic postmortem blood specimens for a time interval of up to six months. The samples were stored in glass vials at -20 degrees C, 4 degrees C, and 20 degrees C. Additionally, spiked samples were exposed to light through window glass and subjected to a forced-degradation study at 40 degrees C. Data were established using solid-phase extraction and high-performance liquid chromatography coupled to atmospheric pressure ionization mass spectrometry for isolation and quantitation, providing a sensitive and specific detection method for the parent drug in the presence of its glucuronide metabolites. Morphine and its glucuronide metabolites were found to be stable in both blood and plasma at 4 degrees C for the whole observation period. In postmortem blood the analytes were stable only when stored at -20 degrees C. The thermal decomposition of morphine and morphine-6-glucuronide in spiked blood and plasma could be interpreted using pseudo first-order kinetics. Photodegradation of morphine-3-glucuronide in plasma was consistent with a second-order reaction. In postmortem samples the degradation pattern differed completely from that observed in fresh blood and plasma. The elevated morphine levels observed were primarily due to postmortem hydrolysis of morphine glucuronides.     

LC-MS法分析拉米夫定的有关物质

目的建立检测拉米夫定中有关物质的液质联用分析方法,分析鉴定拉米夫定原料药、加速破坏样品和制剂产品中的有关物质,并推测其可能的降解途径。方法色谱柱为Syncronjs C_(18)柱,以5 mmol·L^(-1)乙酸铵-甲醇为流动相,线性梯度洗脱,对拉米夫定有关物质进行分离。分别在正负离子模式下采用一级全扫描和自动二级全扫描方式对样品进行质谱检测。结果拉米夫定及其各有关物质分离良好,共检测到13种有关物质。结果表明,拉米夫定的主要降解反应为氧化、差向异构化、脱氨和水解。在酸性和高温条件下,药物的稳定性良好,但在碱性和氧化条件下,药物稳定性较差。制剂产品中有关物质的种类较原料药有显著增加。结论该方法适用于拉米夫定有关物质和降解途径的研究,试验中检测到的有关物质,推测的降解途径及该类物质的质谱行为规律为该产品的质量控制及稳定性研究提供了重要的依据。     

Long-term safety and tolerability of lurasidone in schizophrenia: a 12-month, double-blind, active-controlled study

The aim of this study is to evaluate the long-term safety and tolerability of lurasidone in the treatment of schizophrenia. Clinically stable adult outpatients with schizophrenia were randomized in a 2 : 1 ratio to 12 months of double-blind treatment with once-daily, flexibly-dosed lurasidone (40-120 mg) or risperidone (2-6 mg). Outcome measures included adverse events (AEs), vital signs, ECG, and laboratory tests. Secondary assessments included measures of psychopathology. A total of 427 patients were randomized to treatment with lurasidone and 202 with risperidone. The three most frequent AEs in the lurasidone group (vs. risperidone) were nausea (16.7 vs. 10.9%), insomnia (15.8 vs. 13.4%), and sedation (14.6 vs. 13.9%); the three most frequent AEs in the risperidone group (vs. lurasidone) were increased weight (19.8 vs. 9.3%), somnolence (17.8 vs. 13.6%), and headache (14.9 vs. 10.0%). A higher proportion of patients receiving risperidone had at least a 7% endpoint increase in weight (14 vs. 7%). The median endpoint change in prolactin was significantly higher for risperidone (P<0.001). A comparable improvement in efficacy measures was observed with both agents and the rates of relapse were similar. All-cause discontinuation rates were higher for lurasidone versus risperidone. Long-term treatment with lurasidone was generally well tolerated in this study, with minimal effects on weight and metabolic outcomes.     

Metabolism of the psychotomimetic tryptamine derivative 5-methoxy-N,N-diisopropyltryptamine in humans: identification and quantification of its urinary metabolites.

The urinary metabolites of 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT) in humans have been investigated by analyzing urine specimens from its users. For the unequivocal identification and accurate quantification of its major metabolites, careful analyses were conducted by gas chromatography/mass spectrometry, liquid chromatography/mass spectrometry, and liquid chromatography-tandem mass spectrometry, using authentic standards of each metabolite synthesized. Three major metabolic pathways were revealed as follows: 1) side chain degradation by O-demethylation to form 5-hydroxy-N,N-diisopropyltryptamine (5-OH-DIPT), which would be partly conjugated to its sulfate and glucuronide; 2) direct hydroxylation on position 6 of the aromatic ring of 5-MeO-DIPT, and/or methylation of the hydroxyl group on position 5 after hydroxylation on position 6 of the aromatic ring of 5-OH-DIPT, to produce 6-hydroxy-5-methoxy-N,N-diisopropyltryptamine (6-OH-5-MeO-DIPT), followed by conjugation to its sulfate and glucuronide; and 3) side chain degradation by N-deisopropylation, to the corresponding secondary amine 5-methoxy-N-isopropyltryptamine (5-MeO-NIPT). Of these metabolites, which retain structural characteristics of the parent drug, 5-OH-DIPT and 6-OH-5-MeO-DIPT were found to be more abundant than 5-MeO-NIPT. Although the parent drug 5-MeO-DIPT was detectable even 35 h after dosing, no trace of its N-oxide was detected in any of the specimens examined.     

Isolation and identification of cyclic imide and deamidation products in heat stressed pramlintide injection drug product

This report summarizes the identification of six cyclic imide [Asu] and two deamidation products from a sample of pramlintide final drug product that had been stressed at 40 degrees C for 45 days. The pramlintide degradation products were isolated by cation exchange high-performance liquid chromatography (HPLC) followed by reversed-phase HPLC. The isolated components were characterized by mass spectrometry (MS), tandem MS (MS/MS) and when necessary, by enzymatic (thermolysin) digestion followed by liquid chromatography/mass spectrometry (LC/MS) and sequence analysis. The isolated products were identified as [Asu14]-pramlintide, [Asu21]-pramlintide, [Asu22]-pramlintide, [Asu35]-pramlintide, [1-21]-succinimide-pramlintide, and [1-22]-succinimide-pramlintide. Also identified were [Asp35]-pramlintide, the deamidation product of pramlintide at Asn35, and [Tyr37-OH]-pramlintide, the deamidation product of the pramlintide amidated C-terminal Tyr. Together these data support those presented earlier (C. Hekman et al., Isolation and identification of peptide degradation products of heat stressed pramlintide injection drug product. Pharm Res 1998;15:650-9) indicating that the primary mechanism of degradation for pramlintide in this pH 4.0 formulation is deamidation, with six of the eight possible deamidation sites observed to undergo deamidation. Gln-10 and Asn-31 are the only two residues subject to deamidation for which none is observed. The data indicate that the cyclic imide products account for approximately 20% of the total thermal degradation while the deamidation products account for 64%. The remaining degradation is due to peptide backbone hydrolysis.     

Real-world adherence assessment of lurasidone and other oral atypical antipsychotics among patients with schizophrenia: an administrative claims analysis

Objective: To compare adherence with lurasidone to other oral atypical antipsychotics among Medicaid and commercially insured patients with schizophrenia.

Research design and methods: Administrative claims of patients with schizophrenia treated with atypical antipsychotics (lurasidone, aripiprazole, olanzapine, quetiapine, risperidone, or ziprasidone) from October 2010 to September 2011 were identified from MarketScan Commercial and Medicaid Databases, and were classified by the first (index) antipsychotic. Patients were 18–64 years, had insurance coverage 12 months pre- and 6 months post-index, and no pre-index use of the index drug.

Main outcome measures: Medication possession ratio (MPR), discontinuation rate, and mean time to discontinuation were assessed post-index. Pairwise comparisons (lurasidone versus each drug) were conducted using chi-square tests and Student’s t-tests.

Results: There were 146 Medicaid (mean age 43.5 years, 47.9% female) and 63 commercial (mean age 40.0 years, 42.9% female) patients treated with lurasidone. In the Medicaid population, the MPR for patients treated with lurasidone was 0.60, versus 0.41–0.48 for patients treated with other antipsychotics (all p?p?p?p?p?Conclusions: In Medicaid and commercial populations, patients treated with lurasidone demonstrated greater adherence compared to patients treated with other atypical antipsychotics. Limitations of using administrative claims data include potential errors or inconsistencies in coding, and lack of complete clinical information.     

Application of the Abbott TDx lidocaine, phenytoin, and phenobarbital assays to postmortem blood specimens

The TDx fluorescence polarization immunoassays (FPIA) for some therapeutically monitored drugs (lidocaine, phenytoin, phenobarbital) were applied to the analysis of postmortem blood specimens. After an initial calibration using the appropriate TDx calibrators, blood bank blood fortified with known amounts of drug was analyzed by FPIA. Postmortem blood specimens containing the drugs, postmortem specimens not containing the drugs of interest (negatives), and randomly selected postmortem blood specimens fortified with known amounts of the drugs were analyzed by the FPIA and reference gas chromatographic (GC) methods. Concentrations determined in blood bank and postmortem blood specimens showed excellent correlation between the two methods and produced lines with slopes ranging from 0.98 to 1.08. In each case the correlation coefficient was greater than 0.97. Analysis of all negative specimens produced FPIA values below the limit of quantitation of the reference GC assay.     

Analysis of 30 synthetic cannabinoids in oral fluid using liquid chromatography‐electrospray ionization tandem mass spectrometry

In recent years, the analysis of synthetic cannabinoids in human specimens has gained enormous importance in the broad field of drug testing. Nevertheless, the considerable structural diversity among synthetic cannabinoids already identified in ‘herbal mixtures’ hampers the development of comprehensive analytical methods. As the identification of the main metabolites of newly appearing substances is very laborious and time‐consuming, the detection of the parent compounds in blood samples is the current approach of choice for drug abstinence testing. Whenever blood sampling is not possible however, the need for alternative matrices arises. In this article, we present a fully validated liquid chromatography‐electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS) method for the analysis of 30 synthetic cannabinoids in oral fluid samples collected with the Dräger DCD 5000 collection device. The method proved to be suitable for the quantification of 28 substances. The limits of detection were in the range from 0.015 to 0.9 ng/ml, while the lower limits of quantification ranged from 0.15 to 3.0 ng/ml. The method was successfully applied to 264 authentic samples during routine analysis. A total of 31 samples (12%) was tested positive for at least one of the following synthetic cannabinoids: AM‐694, AM‐2201, JWH‐018, JWH‐019, JWH‐081, JWH‐122, JWH‐203, JWH‐210, JWH‐250, JWH‐307, MAM‐2201, and RCS‐4. Given that stabilization of the collection pads after sampling is warranted, the collection device provides satisfactory sensitivity. Hence, whenever blood sampling is not possible, the Dräger DCD 5000 collection device offers a good tool for the analysis of synthetic cannabinoids in oral fluid in the broad field of drug testing. Copyright © 2012 John Wiley & Sons, Ltd.     

Profiling impurities and degradants of butorphanol tartrate using liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry substructural techniques

A rapid and systemic strategy based on liquid chromatography/mass spectrometry (LC/MS) profiling and liquid chromatography/tandem mass spectrometry (LC/MS/MS) substructural techniques was utilized to elucidate the degradation products of butorphanol, the active ingredient in stadol® NS. This strategy integrates, in a single instrumental approach, analytical HPLC, UV detection, full-scan electrospray mass spectrometry, and tandem mass spectrometry to rapidly and accurately elucidate structues of impurities and degradants. In these studies, several low-level degradation products were observed in long-term storage stability samples of bulk butorphanol. The resulting analytical profile includes information on five degradants including molecular structures, chromatographic behavior, molecular weight, UV data, and MS/MS substructural information. The degradation products formed during long-term storage of butorphanol tartrate included oxidative products proposed as 9-hydroxy- and 9-keto-butorphanol, norbutorphanol, a ring-contraction degradant, and Δ1, 10-butorphanol. These methodologies are applicable at any stage of the drug product cycle from discovery through to development. This library of butorphanol degradants provides a foundation for future development work regarding product monitoring, as well as a useful diagnosite tool for new degradation products.     

Investigation of an LC-MS-MS (QTrap) method for the rapid screening and identification of drugs in postmortem toxicology whole blood samples

The QTrap liquid chromatography-tandem mass spectrometry (LC-MS-MS) by Applied Biosystems was investigated as an adjund to enzyme immunoassay (EIA) for the rapid detection of drugs in blood. Thus, a procedure used to identify drugs in whole blood by EIA was extended to LC-MS-MS analysis. A multiple reaction monitoring (MRM) database of over 100 drugs was constructed to analyze for those drugs commonly observed in postmortem toxicology cases. The QTrap method provided for a scan time of only 2.8 s to produce both an MRM and an enhanced product ion scan. Various validation and developmental steps of the method are presented, as well as a concordance study as a final means of validation. This study was conducted to compare the effectiveness of the QTrap versus conventional extraction methods and gas chromatography-MS for the identification of drugs in 95 postmortem samples. The more than 400 drug results in this study showed 100% concordance between the two techniques.     

Postmortem metabolomics: Correlating time‐dependent concentration changes of xenobiotic and endogenous compounds

Postmortem redistribution (PMR) describes the artificial postmortem concentration changes of xenobiotics that may pose major challenges in forensic toxicology. Only a few studies have systematically investigated time‐dependent postmortem drug concentration changes so far and the a posteriori estimation of the occurrence of PMR is not yet possible. In this context, the general concept that postmortem biochemical changes in blood might parallel drug redistribution mechanisms seems promising. Thus, the current study investigated the possible correlations between time‐dependent postmortem concentration changes of xenobiotic and endogenous compounds; exemplified for authentic morphine (n = 19) and methadone (n = 11) cases. Peripheral blood samples at two time‐points postmortem were analyzed for morphine and methadone concentrations and an (un)targeted postmortem metabolomics approach was utilized to combine targeted quantitative analysis of 56 endogenous analytes and untargeted screening for endogenous compounds (characterizing 1174 features); liquid and gas chromatography–mass spectrometry was used respectively. Individual statistically significant correlations between morphine/methadone and endogenous compounds/features could be determined. Hence, the general applicability of the proposed concept could successfully be confirmed. To verify the reproducibility and robustness of the correlating behavior, a larger dataset must be analyzed next. Once a marker/set of markers is found (e.g. robust correlation with specific xenobiotic or xenobiotic class), these could be used as surrogates to further study the time‐dependent PMR in a broader variety of cases (e.g. independent of a xenobiotic drug present). A crucial next step will also be the attempt to create a statistical model that allows a posteriori estimation of PMR occurrence of xenobiotics to assist forensic toxicologists in postmortem case interpretation.     

Impurities in a Lyophilized Formulation of BMS-204352: Identification and Role of Sanitizing Agents

The purpose of this study was to identify two impurities in the parenteral lyophilized formulation of BMS-204352, investigate the role of sanitizing agents as their potential source, evaluate their effect on drug product stability, and develop a strategy to prevent their contamination of the drug product. The two impurities were identified as o-phenylphenol and 4-t-amylphenol based on liquid chromatography/mass spectroscopy (LC/MS) and chromatographic comparison to authentic samples. The LC/MS spectra of commercially available o-phenylphenol and 4-t-amylphenol showed identical patterns of fragmentation and the same retention times as the impurities identified in the BMS-204352 lyophilized product. Levels of these impurities were low and ranged between 0.2–0.3 μg/vial as determined by HPLC and using an authentic external reference standard. To confirm the hypothesis that the commercial sanitizing agents used in the sterile area were the source of these phenolic impurities, several product samples were spiked with the sanitizing agents. Both o-phenylphenol and 4-t-amylphenol were detected in the spiked samples. Further investigation revealed that o-phenylphenol and 4-t-amylphenol are active ingredients of these commercial sanitizing agents. Drug product samples containing the phenolic impurities showed no potency loss following storage at 30, 50, and 70°C indicating these impurities had no adverse effect on product stability. These studies suggest that sanitizing agents used in the sterile area, although may be present at trace levels below typical cleaning procedure detection methods, need to be properly controlled and closely monitored during the manufacturing of injectable products, particularly highly potent drugs. Sanitizing agents, even though not used on product contact surfaces, may potentially contaminate a product through vapor transfer in an open environment.     

LC and LC–MS/TOF studies on stress degradation behaviour of candesartan cilexetil

Stress degradation studies were conducted on candesartan cilexetil under the ICH prescribed conditions of hydrolysis (acidic, basic and neutral), photolysis, oxidation and thermal stress. Maximum degradation was observed on hydrolysis, especially in the neutral condition. The drug was also degraded significantly under photolytic conditions. However, it was stable to oxidative and thermal stress. A total of eight degradation products were formed, the separation of which was successfully achieved on a C-18 column employing a gradient method. In order to characterize each degradation product, a complete mass fragmentation pathway of the drug was initially established with the help of MSⁿ and MS/TOF accurate mass studies. Subsequently, degradation products were also subjected to LC–MS/TOF investigations, which resulted in their fragmentation pattern and also accurate masses. The latter helped in the elucidation of the structure of all the degradation products, which was achieved through comparison of their fragmentation pattern with that of the drug. The major product was isolated and its structure was confirmed through NMR studies. On the whole, a more comprehensive fragmentation behaviour and degradation profile of the drug was established than reported in the literature.     

Degradation of a lyophilized formulation of BMS-204352: identification of degradants and role of elastomeric closures

The purpose of this study was to identify two degradation products formed in the parenteral lyophilized formulation of BMS-204352, investigate the possible role of elastomeric closures in their formation, and develop a strategy to minimize/control their formation. The first degradant was identified as the hydroxymethyl derivative (formaldehyde adduct, BMS-215842) of the drug substance formed by the reaction of BMS-204352 with formaldehyde. Structure confirmation was based on liquid chromatography/mass spectroscopy (LC/MS), nuclear magnetic resonance (NMR), and chromatographic comparison to an authentic sample of the hydroxymethyl degradation product, BMS-215842. To confirm the hypothesis that formaldehyde originated from the rubber closure, migrated into the product, and reacted with BMS-204352 drug substance to form the hydroxymethyl degradant, lyophilized drug product was manufactured, the vials were stoppered with two different rubber closure formulations, and its stability was monitored. The formaldehyde adduct degradant was observed only in the drug product vials stoppered with one of the rubber closures that was evaluated. Although formaldehyde has not been detected historically as leachable and is not an added ingredient in the rubber formulation, information obtained from the stopper manufacturer indicated that the reinforcing agent used in the stopper formulation may be a potential source of formaldehyde. The second degradant was identified as the desfluoro hydroxy analog (BMS-188929) based on LC/MS, NMR, and chromatographic comparison to an authentic sample of the desfluoro hydroxy degradation product.     

A Novel Oral Fluid Assay (LC-QTOF-MS) for the Detection of Fentanyl and Clandestine Opioids in Oral Fluid After Reported Heroin Overdose

Introduction

The adulteration of heroin with non-pharmaceutical fentanyl and other high-potency opioids is one of the factors contributing to striking increases in overdose deaths. To fully understand the magnitude of this problem, accurate detection methods for fentanyl and other novel opioid adulterant exposures are urgently required. The objective of this work was to compare the detection of fentanyl in oral fluid and urine specimens using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) in a population of heroin users presenting to the Emergency Department after overdose.

Methods

This was a prospective observational study of adult Emergency Department patients who presented after a reported heroin overdose requiring naloxone administration. Participants provided paired oral fluid and urine specimens, which were prepared, extracted, and analyzed using a dual LC-QTOF-MS workflow for the identification of traditional and emerging drugs of abuse. Analytical instrumentation included SCIEX TripleTOF® 5600+ and Waters Xevo® G2-S QTOF systems.

Results

Thirty participants (N = 30) were enrolled during the study period. Twenty-nine participants had fentanyl detected in their urine, while 27 had fentanyl identified in their oral fluid (overall agreement 93.3%, positive percent agreement 93.1%). Cohen’s Kappa (k) was calculated and demonstrated moderately, significant agreement (k = 0.47; p value 0.002) in fentanyl detection between oral fluid and urine using this LC-QTOF-MS methodology. Additional novel opioids and metabolites, including norfentanyl, acetylfentanyl, and U-47700, were detected during this study.

Conclusion

In this study of individuals presenting to the ED after reported heroin overdose, a strikingly high proportion had a detectable fentanyl exposure. Using LC-QTOF-MS, the agreement between paired oral fluid and urine testing for fentanyl detection indicates a role for oral fluid testing in surveillance for nonpharmaceutical fentanyl. Additionally, the use of LC-QTOF-MS allowed for the detection of other clandestine opioids (acetylfentanyl and U-47700) in oral fluid.

     

Characterization of dark liver pigment observed in rats after subchronic dosing of the beta3-adrenergic receptor agonist LY368842

Dark liver pigmentation was observed in F344 rats in a subchronic toxicology study after daily dosing of LY368842 glycolate. In addition, green-colored urine was observed in some animals. To identify the source of the pigment and its potential for toxic consequences, the liver pigment was isolated from the liver tissue of rats. The resulting material was a dark brown to black powder that was insoluble in water, organic solvents, or a tissue-solubilizing agent. Several techniques, such as chemical degradation, HPLC, tandem mass spectrometry (LC/MS/MS), (1)H NMR, and matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), were employed to characterize the dark liver pigment. Following oxidative degradation of the isolated pigment, degradation products related to LY368842 were identified or tentatively identified using LC/MS/MS. Two degradation products had the same protonated molecular ion at m/z 505, which is 30 amu higher than that of LY368842. The major m/z 505 product has been identified as the indole-2,3-dione oxidative product based on (1)H NMR data and confirmed by an authentic standard. In addition, monohydroxylated product was also identified in the degradation mixture. These degradation products were consistent with the metabolites found in vivo in rats. MALDI-MS analyses of liver and urine pigment both identified a product with a protonated molecular ion at m/z 977, suggesting formation of indirubin-like and indigo-like pigments. The results obtained suggest that the oxidative metabolites of LY368842 played a key role in the formation of the liver and urine pigments.     

The use of dried blood spots for quantification of 15 antipsychotics and 7 metabolites with ultra‐high performance liquid chromatography ‐ tandem mass spectrometry

Therapeutic drug monitoring of antipsychotics is important in optimizing individual therapy. In psychiatric populations, classical venous blood sampling is experienced as frightening. Interest in alternative techniques, like dried blood spots (DBS), has consequently increased. A fast and easy to perform DBS method for quantification of 16 antipsychotics (amisulpride, aripiprazole, asenapine, bromperidol, clozapine, haloperidol, iloperidone, levosulpiride, lurasidone, olanzapine, paliperidone, pipamperone, quetiapine, risperidone, sertindole and zuclopenthixol) and 8 metabolites was developed. DBS were prepared using 25 μL of whole blood and extraction of complete spots was performed using methanol: methyl‐t‐butyl‐ether (4:1). After evaporation, the extract was reconstituted in the mobile phase and 10 μL were injected on an ultra‐high performance liquid chromatography‐tandem mass spectrometry (UHPLC‐MS/MS). Separation using a C18 column and gradient elution with a flow rate of 0.5 mL/min resulted in a 6‐min run‐time. Ionization was performed in positive mode and a dynamic MRM method was applied. Median recovery was 66.4 % (range 28.7‐84.5%). Accuracy was within the acceptance criteria, except for pipamperone (LLOQ and low concentration) and lurasidone (low concentration). Imprecision was only aberrant for lurasidone at low and medium concentration. All compounds were stable during 1 month at room temperature, 4 °C and ?18 °C. Lurasidone was unstable when the extract was stored for 12 h on the autosampler. Absolute matrix effects (ME) (median 66.1%) were compensated by the use of deuterated IS (median 98.8%). The DBS method was successfully applied on 25‐μL capillary DBS from patients and proved to be a reliable alternative for quantification of all antipsychotics except for olanzapine and N‐desmethylolanzapine. Copyright © 2014 John Wiley & Sons, Ltd.