[Show abstract][Hide abstract] ABSTRACT: Here we rationally evaluate surface-enhanced Raman spectroscopy (SERS) substrates in terms of limit of detection (LOD), limit of identification (LOI) and dynamic range for ten common narcotic drug analytes. The drugs were amphetamine, cocaine, methadone, diazepam, methylphenidate, oxazepam, tramadol, morphine, buprenorphine and 6-monoacetylmorphine. A Raman microscope system was complemented with portable instrumentation, both in conjunction with commercial SERS substrates, and, by vibrational peak assignments, the functionality of substrates and pureness of samples was ensured. The dynamic range is explored qualitatively by concentration series measurements, where the Langmuir adsorption isotherm provided good fits. Moreover, an output fit parameter, the inverse of Langmuir constant, was found to roughly scale with LOD and can therefore be helpful in SERS substrate evaluations. Four different statistical methodologies were tested to estimate LOD: (i) a general formula to calculate a one-sided prediction interval for the mean value of blanks (LODB), (ii–iii) calculated from a one-sided prediction interval (at significance level 0.05) of a linear regression line, where the obtained limit of detection in the signal domain was sometimes outside the linear concentration range, which is why the corresponding concentration was calculated from (ii) a linear calibration curve (LODLR) and (iii) a non-linear calibration curve (LODNR), and (iv) using receiver operating characteristic (ROC) curves to estimate LODROC. Here, a new optimization approach was introduced for LODROC estimation, based on interpolation and thus better suited to handle a few data points spanning a large concentration range. LOI was assessed by discriminant analysis of partial least squares (PLS-DA) classification for seven of the drug compounds using PLS-DA, and the extracted LOIs were found to be higher than the LODs and were varying with respect to accuracy of the model which is strongly correlated to the probability of false positive detection that can be accepted.
Sensors and Actuators B Chemical 02/2015; 207. · 3.84 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aim. Exhaled breath has recently been identified as a possible matrix for drug testing. This study explored the potential of this new method for compliance monitoring of patients being treated for dependence disorders. Methods. Outpatients in treatment programs were recruited for this study. Urine was collected as part of clinical routine and a breath sample was collected in parallel together with a questionnaire about their views of the testing procedure. Urine was analyzed for amphetamines, benzodiazepines, cannabis, cocaine, buprenorphine, methadone and opiates using CEDIA immunochemical screening and mass spectrometry confirmation. The exhaled breath was collected using the SensAbues device and analyzed by mass spectrometry for amphetamine, methamphetamine, diazepam, oxazepam, tetrahydrocannabinol, cocaine, benzoylecgonine, buprenorphine, methadone, morphine, codeine and 6-acetylmorphine. Results. A total of 122 cases with parallel urine and breath samples were collected; 34 of these were negative both in urine and breath. Out of 88 cases with positive urine samples 51 (58%) were also positive in breath. Among the patients on methadone treatment, all were positive for methadone in urine and 83% were positive in breath. Among patients in treatment with buprenorphine, 92% were positive in urine and among those 80% were also positive in breath. The questionnaire response documented that in general, patients accepted drug testing well and that the breath sampling procedure was preferred. Conclusion. Compliance testing for the intake of prescribed and unprescribed drugs among patients in treatment for dependence disorders using the exhaled breath sampling technique is a viable method and deserves future attention.
Scandinavian journal of clinical and laboratory investigation. 01/2015;
[Show abstract][Hide abstract] ABSTRACT: Morphine is still the mainstay in treatment of severe pain and is metabolized in the liver mainly by glucuronidation, partly to the pharmacologically active morphine-6-glucuronide (M6G). The sulfation pathway has attracted much less attention but may also form active metabolites. The aim of the present study was to study two sulfate metabolites of morphine in humans. Urine and plasma from newborns, adult heroin addicts, and terminal cancer patients was analyzed for the presence of morphine-3-sulfate (M3S) and morphine-6-sulfate (M6S) by a new liquid chromatography – tandem mass spectrometry (LC-MS/MS) method. In addition, morphine sulfation was studied in vitro in human liver cytosol preparations. M3S was present in urine and plasma from all study groups although at lower concentrations than morphine-3-glucuronide (M3G). The plasma M3S/M3G ratio was 30 times higher in newborns than in adults indicating that the relative sulfation is more important at early stage of life. M6S was measurable in only one plasma sample from a newborn patient, and in one of the urine sample from the drug testing group. The incubation of morphine with liver cytosol extracts resulted in approximately equal rate of formation of both M3S and M6S. In conclusion, sulfation of morphine is catalyzed in human liver but this minor metabolic pathway probably lacks clinical significance. The M6S metabolite is formed at a low rate, making it undetectable in most individuals.
Pharmacology Research & Perspectives. 12/2014; 2(6).
[Show abstract][Hide abstract] ABSTRACT: Background. 3-Methylmethcathinone (3-MMC) is a synthetic cathinone stimulant structurally related to the new psychoactive substance (NPS) mephedrone (4-methylmethcathinone, 4-MMC). We describe a case series of analytically confirmed intoxications involving 3-MMC presented to emergency departments in Sweden and included in the STRIDA project. Study design. Observational case series of consecutive patients with self-reported or suspected use of NPS presenting to hospitals in Sweden between August 2012 and March 2014. Methods. NPS analysis was performed by a liquid chromatography-mass spectrometry (MS)/MS method that is updated with new substances as they appear. Data on clinical features were collected during Poisons Information Centre consultations and retrieved from medical records. Results. 3-MMC was detected in 50 (6.4%) of the 786 cases included in the STRIDA project during the 20-month study period, with the peak occurring in August 2013. The age range of patients testing positive for 3-MMC was 17-49 years (median 24) and 76% of them were men. The 3-MMC concentration in serum ranged between 0.002 and 1.49 μg/mL (median, 0.091) and between 0.007 and 290 μg/mL (median, 3.05) in urine. Co-exposure to other NPS and/or traditional drugs was very common, and 3-MMC mono-intoxication was found in only 4 (8%) cases. The most frequent clinical features were tachycardia (48% of cases) and agitation (42%). Other features included a reduced level of consciousness (32%), dilated pupils (24%), hallucinations (20%), diaphoresis (12%), seizures (8%), and hyperthermia (6%). Most patients (60%) needed hospital care for only 1 day but in 8% for 3 days or longer. Conclusion. The majority of patients with analytically confirmed 3-MMC exposure had sympathomimetic features similar to those associated with mephedrone intoxication. However, the high incidence of co-exposure to other drugs makes the clinical interpretation difficult. Nevertheless, 3-MMC was associated with a high admittance rate to intensive care (30%), and detected in two cases with a fatal outcome, suggesting that 3-MMC is a harmful drug.
[Show abstract][Hide abstract] ABSTRACT: The “STRIDA” project monitors the occurrence and trends of new psychoactive substances (NPS; “Internet drugs/designer drugs/legal highs”) in Sweden, and collects information about their clinical symptoms, toxicity and associated health hazards. The initial results of the project documented a widespread use of many different NPS by mainly adolescents and young (age range 13–63 years, median 20), male (79%) adults, among cases of drug intoxications presenting at emergency departments and intensive care units across the country. The new substances were identified in samples of urine and blood by a multi-component LC-MS/MS method, and the severity of clinical symptoms were graded by the Poisoning Severity Score (PSS). Of the initial 189 samples submitted for laboratory investigation, 156 (83%) tested positive for at least one drug. Besides classical substances such as ethanol, cannabis and amphetamines, many NPS were detected comprising synthetic cannabinoid receptor agonists (“Spice”), piperazines, substituted phenethylamines, synthetic cathinones, hallucinogenic tryptamines, piperidines, opioid related substances, ketamine and related substances, and GABA analogues (in total more than 50 substances). About half of the cases were demonstrated to be multiple drug intoxications, sometimes making it hard to associate the clinical presentations with one specific substance. In conclusion, the STRIDA project has documented use of a broad variety of NPS among mainly young people all over Sweden.
Forensic science international 10/2014; · 2.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Introduction
The oral direct thrombin inhibitor dabigatran is increasingly used to prevent thromboembolic stroke in patients with atrial fibrillation (AF). Routine laboratory monitoring is currently not recommended, but measurements of dabigatran and/or its effect are desirable in certain situations. We studied dabigatran exposure and compared different tests for monitoring of dabigatran in a real-life cohort of AF patients.
Material and methods
Ninety AF patients (68 ± 9 years, 67% men, mean CHADS2 score 1.5) were treated with dabigatran 150 (n = 73) or 110 mg BID (n = 17). Trough plasma concentrations of total and free dabigatran by liquid chromatography-tandem mass-spectrometry (LC-MS/MS) were compared to indirect measurements by Hemoclot thrombin inhibitors (HTI) and Ecarin clotting assay (ECA), as well as PT-INR and aPTT.
Total plasma dabigatran varied 20-fold (12–237 ng/mL with 150 mg BID) and correlated well with free dabigatran (r2 = 0.93). There were strong correlations between LC-MS/MS and HTI or ECA (p < 0.001) but these assays were less accurate with dabigatran below 50 ng/mL. The aPTT assay was not dependable and PT-INR not useful at all. There were weak correlations between creatinine clearance (Cockcroft-Gault) and LC-MS/MS, HTI and ECA (p < 0.001 for all). A high body weight with normal kidney function was associated with low dabigatran levels.
HTI and ECA reflect the intensity of dabigatran anticoagulation, but LC-MS/MS is required to quantify low levels or infer absence of dabigatran. Most real life patients with a normal creatinine clearance had low dabigatran levels suggesting a low risk of bleeding but possibly limited protection against stroke.
[Show abstract][Hide abstract] ABSTRACT: Exhaled breath has recently been proposed as a matrix for drug testing. This study aims to further explore, develop and validate exhaled breath as a safe and effective non-invasive method for drug testing in a clinical setting. Self-reported drug use was recorded and drug testing was performed by mass spectrometry and immunochemical methods using breath, plasma and urine samples from 45 individuals voluntarily seeking treatment for recreational drug use. Cannabis was the most prevalent drug detected by any method. Urine sampling detected most cases. The exhaled breath technique was less sensitive (73%) than plasma analysis for detection of cannabis uses but captures a more recent drug intake than both plasma and urine. Exhaled breath was the preferred specimen to donate according to interview data of the participants. Testing illicit drugs with the exhaled breath sampling technique is a sufficient, non-invasive and safe alternative and complement to plasma and/or urine sampling.
Journal of Substance Abuse Treatment 09/2014; · 3.14 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A semi-automated method for quantification of budesonide in human plasma was developed, validated, and applied for high-volume analysis of samples in connection with a pharmacokinetic study. Protein and phospholipid removal was performed using an Ostro 96-well filter plate and subsequently combined with C18 solid-phase extraction on a Hamilton Microlab STARlet automation robot. The final extracts were evaporated to dryness and redissolved in 20% acetonitrile/water. The procedure used budesonide-d8 as internal standard and gave a 3.5-fold concentration of plasma to extract. The final extracts (5μL injected) were analyzed with selected reaction monitoring liquid chromatography-tandem mass spectrometry (LC-MS/MS) using electrospray ionization in positive mode. The chromatography system used a 100mm ACQUITY BEH UPLC column and a gradient system consisting of aqueous 0.1% formic acid and acetonitrile as organic modifier. Phospholipid removal was found to be needed during method development in order to reduce ion suppression effects from matrix and to increase method sensitivity. The measuring range was 50-5000pg/mL with and LOD 24pg/mL. Calibration response showed good linearity (correlation coefficients<0.99) over the measuring range. The absolute recovery over the sample preparation procedure was estimated to 67%. Total imprecision was <9% at three levels and accuracy was between 98.9 and 103%. The method was successfully applied for analysis of 864 study samples in a short time. The quality control samples at concentration levels 200 and 2000pg/mL gave a total imprecision of 7.4% and 4.2%, respectively, (n=95).
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 09/2014; 970C:31-35. · 2.78 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract
Assess association between UGT2B7 polymorphism -900G>A (rs7438135, also known as -842G>A) with morphine kinetics in preterm newborns undergoing mechanical ventilation.
MATERIALS & METHODS:
Thirty-four infants were enrolled in a randomized clinical trial and allocated to rapid sequence intubation with remifentanil (1 µg/kg) or morphine (0.3 mg/kg). The latter group was included in our study.
Morphine plasma concentrations at 20 min post intubation were associated with postnatal age (p = 0.017) and UGT2B7 -900G>A (p = 0.036). UGT2B7 -900A allele carriers (n = 13) had lower morphine levels compared with UGT2B7 -900G/G patients (n = 2). Morphine-3-glucuronide and morphine-6-glucuronide plasma concentrations were only found to be associated with gestational and postnatal age. However, -900A allele carriers had a higher morphine-3-glucuronide:morphine metabolic ratio compared with patients genotyped as -900G/G (p = 0.005), as determined by linear regression.
Our small pilot study illustrates that in addition to gestational and postnatal age, the UGT2B7 -900G>A polymorphism significantly alters morphine pharmacokinetics in preterm infants. Original submitted 8 April 2014; Revision submitted 22 July 2014.
[Show abstract][Hide abstract] ABSTRACT: Background. MT-45 (1-cyclohexyl-4-(1,2-diphenylethyl)piperazine) is an opioid analgesic drug candidate developed in the 1970s that has recently been introduced as a new psychoactive substance (NPS) on the "recreational" drug market. We describe a case series of non-fatal intoxications associated with MT-45 within the Swedish STRIDA project. Study design. Observational case series of consecutive patients with admitted or suspected intake of NPS presenting to hospitals in Sweden from November 2013 to February 2014. Patients and methods. Blood and urine samples were collected from intoxicated patients presenting to emergency departments and intensive care units over the country. NPS analysis was performed by an LC-MS/MS multi-component method. Clinical data were collected when caregivers consulted the Poisons Information Centre and also retrieved from medical records. Case series. Among nine intoxications where MT-45 was detected in the biological samples, four cases were indicated to only involve MT-45, while one or several psychoactive substances were found along with MT-45 in the others. All patients were men aged 17-32 years and they commonly presented with opioid-like adverse symptoms, such as unconsciousness and respiratory depression. Naloxone appeared to have utility in the treatment of MT-45 intoxication in several cases. Three patients complained of bilateral hearing loss that in one case persisted after two weeks. Conclusion. MT-45 should be added to the growing list of harmful NPS causing life-threatening poisonings, and rapid actions taken to make it a controlled substance.
[Show abstract][Hide abstract] ABSTRACT: Breath has been investigated as an alternative matrix for detecting recent cocaine intake; however, there are no controlled cocaine administration studies that investigated the drug's disposition into breath. Breath was collected from 10 healthy adult cocaine users by asking them to breathe into a SensAbues device for 3 min before and up to 22 h following 25 mg intravenous (IV) cocaine dosing on days 1, 5, and 10, and assayed with a validated liquid chromatography-high-resolution mass spectrometry (LC-HRMS) method to quantify breath cocaine, benzoylecgonine (BE), ecgonine methyl ester (EME), and norcocaine. The assay was linear from 25 to 1,000 pg/filter, extraction efficiencies were 83.6-126 %, intra- and inter-assay imprecision was <10.6 %, and bias was between -8.5 and 16.8 %. No endogenous or exogenous interferences were observed for more than 75 tested. Analytes were generally stable under short-term storage conditions. Ion suppression was less than 46 %. Of breath specimens collected after controlled cocaine administration, 2.6 % were positive for cocaine (26.1-66 pg/filter, 1-9.5 h), 0.72 % BE (83.3-151 pg/filter, 6.5-12.5 h), and 0.72 % EME (50-69.1 pg/filter, 6.5-12.5 h); norcocaine was not detected. Methanolic extraction of the devices themselves, after filters were removed, yielded 19.2 % positive cocaine tests (25.2-36.4 pg/device, 10 min-22 h) and 4.3 % positive BE tests (26.4-93.7 pg/device, 10 min-22 h), explaining differences between the two extraction techniques. These results suggest that the device reflects the drug in oral fluid as well as lung microparticles, while the filter reflects only drug-laden microparticles. A sensitive and specific method for cocaine, BE, EME, and norcocaine quantification in breath was developed and validated. Cocaine in breath identifies recent cocaine ingestion, but its absence does not preclude recent use.
Analytical and Bioanalytical Chemistry 08/2014; · 3.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The advent of LC combined with MS made it possible to design analytical methods for urine drug testing based on the very simple concept of diluting urine with an internal standard as the sole preparation procedure prior to instrumental analysis. The number of publications using this method design increased after the development of high-efficiency LC based on sub-2 μm particles. The success of this method design for drug testing, doping control and toxicological investigations of urine is now well documented and comprise both screening and confirmation methods. The nondiscriminating nature of this method design makes it even more attractive in combination with high-resolution MS for multicomponent target and general unknown analysis applications.
[Show abstract][Hide abstract] ABSTRACT: Background. Therapeutic drug monitoring (TDM) of the antiepileptic drug valproic acid (VPA) is recommended in patients with multiple drug therapy or with concomitant disabilities to ensure treatment efficacy and avoid adverse reactions in both adults and children. The use of sampling techniques compatible with home sampling, such as dried blood spot sampling could potentially facilitate this for patients. Aim. To assess the usefulness of a bioanalytical method for quantification of VPA in dried blood spots. Materials and methods. Quantification was based on liquid chromatography-mass spectrometry (LC-MS), both for the DBS method and the plasma-based reference method. Results. The method was validated in the range 10–1200 μmol/L. Total imprecision ranged from 4.9–8.9 (%CV) and accuracy was within ± 14%. Conclusion. The validated method has potential for evaluation in therapeutic drug monitoring in combination with home sampling of DBS. The impact of spot size can be controlled through acceptance criteria and hematocrit in the range 30–60% can be accepted in sampling. Comparison of VPA levels between plasma and whole blood cannot be done without considering the blood-plasma ratio.
Scandinavian Journal of Clinical and Laboratory Investigation 07/2014; · 2.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aim. Products for on-site urine drug testing offer the possibility to perform screening for drugs of abuse directly at the point-of-care. This is a well-established routine in emergency and dependency clinics but further evaluation of performance is needed due to inherent limitations with the available products. Methods. Urine drug testing by an on-site product was compared with routine laboratory methods. First, on-site testing was performed at the laboratory in addition to the routine method. Second, the on-site testing was performed at a dependency clinic and urine samples were subsequently sent to the laboratory for additional analytical investigation. Results. The on-site testing products did not perform with assigned cut-off levels. The subjective reading between the presence of a spot (i.e. negative test result) being present or no spot (positive result) was difficult in 3.2% of the cases, and occurred for all parameters. The tests performed more accurately in drug negative samples (specificity 96%) but less accurately for detecting positives (sensitivity 79%). Of all incorrect results by the on-site test the proportion of false negatives was 42%. The overall agreement between on-site and laboratory testing was 95% in the laboratory study and 98% in the clinical study. Conclusion. Although a high degree of agreement was observed between on-site and routine laboratory urine drug testing, the performance of on-site testing was not acceptable due to significant number of false negative results. The limited sensitivity of on-site testing compared to laboratory testing reduces the applicability of these tests.
Scandinavian Journal of Clinical and Laboratory Investigation 07/2014; · 2.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Context. 5-(2-aminopropyl)indole (5-IT) is a new psychoactive substance (NPS; "legal high" or "research chemical") structurally related to indoleamines and substituted phenethylamines and implicated in several fatalities. We describe the clinical characteristics and results of laboratory investigations of 14 analytically confirmed nonfatal cases of 5-IT intoxication within the Swedish STRIDA project. Study design. Observational case series of consecutive patients with admitted or suspected intake of NPS presenting to hospitals in Sweden in 2012. Patients and methods. Blood and/or urine samples were collected from intoxicated patients presenting to emergency departments and intensive care units over the country. Analysis of NPS was performed using an LC-MS/MS multi-component method. Clinical data were collected when caregivers consulted the Poisons Information Centre and also retrieved from medical records. The severity of poisoning was graded retrospectively using the Poisoning Severity Score (PSS). Results. Eleven male and three female patients (age: 21-53 years, median: 27) tested positive for 5-IT in 2012, all cases appearing in April-July. The 5-IT concentration in serum ranged between 0.015 and 0.59 μg/mL (median: 0.22; n = 8) and in urine between 0.005 and 24.7 μg/mL (median: 5.95; n = 12). Five intoxications were indicated to be caused by 5-IT alone, whereas additional psychoactive substances were detected in the other nine cases. Six (43%) of fourteen cases were graded as severe (PSS 3), five (36%) as moderate (PSS 2), and three (21%) as minor (PSS 1) poisonings. In the severe cases, agitation, hallucinations, dilated pupils without light reaction, tachycardia, hypertension, hyperthermia, myoclonus, muscle rigidity, arrhythmias, seizures, rhabdomyolysis, and/or renal failure were noted. Conclusions. The results demonstrated that severe clinical toxicity was commonly present in patients with analytically confirmed 5-IT exposure. The clinical features are consistent with a sympathomimetic toxidrome, and some patients also displayed symptoms associated with serotonin toxicity.
[Show abstract][Hide abstract] ABSTRACT: Introduction
Δ9-tetrahydrocannabinol (THC) can be measured in exhaled breath by using a simple aerosol particle collection device. The sampling procedure is simple, non-invasive and takes only 2–3 minutes. In the present study we measured the amount of THC in exhaled breath of cannabis users at specific time intervals up to three hours after smoking one cannabis cigarette. The breath concentration-effect relationship was studied by measuring the pulse rate and the pupil diameter to assess physiological changes.
Participants smoked self-supplied cannabis cigarettes, with an estimated content of 13 to 52 mg of THC, corresponding to 248 μg/kg to 693 μg/kg. They smoked a cigarette outside for 5–10 minutes and directly after smoking, were called inside for breath sampling and physiological tests. Breath sampling was performed before smoking, directly after smoking and 15, 30, 60, 120, 180 minutes after smoking, with a SensAbues DrugTrap® device (SensAbues AB, Huddinge, Sweden). The subjects were asked to breathe via a mouthpiece into a plastic bag for 2 to 3 minutes (± 20 L of exhaled breath). THC was analyzed in exhaled breath by liquid chromatography-tandem mass spectrometry (Beck O et al. Journal of breath research. 2013;7(2):026006.). Thirteen subjects (9 males and 4 females, aged 23–24 years) have participated.
THC was detected in all breath samples but no THCCOOH (<LOD) was found in any sample. The mean THC concentrations were 1043, 27670, 14292, 10982, 4192, 3861 and 1479 pg/filter before, immediately after and 15, 30, 60, 120 and 180 minutes after smoking. THC remained detectable for over three hours after smoking. Pulse rate (p = 0.015) and pupil diameter (p = 0.011) were significantly altered up to 30 minutes after smoking. The mean THC breath concentration showed a counter-clock wise hysteresis relationship with the mean pulse rate.
The detection window of cannabis in breath after smoking one cannabis cigarette in occasional and chronic smokers was at least 3 hours. Only tetrahydrocannabinol, not the metabolite, was detected. The tetrahydrocannabinol concentration in exhaled breath was related to the physiological changes that occur over time by a counterclockwise hysteresis loop. Exhaled breath can be used to detect recent cannabis exposure.
Toxicologie Analytique et Clinique. 06/2014; 26(2):S17–S18.
[Show abstract][Hide abstract] ABSTRACT: It has been discovered recently that exogenous substances are detectable in exhaled breath after intake. Exhaled breath therefore constitutes a new possible matrix in clinical pharmacology and toxicology. The present work was aimed at exploring this possibility further by a study on patients treated for attention-deficit/hyperactivity disorder with D-amphetamine and methylphenidate.
Thirteen patients (age range: 32-61 years; 5 women) were included in the study, and breath and urine samples were collected at different times in the dose interval. Analyses of breath and urine samples were done with liquid chromatography-mass spectrometry methods. Urine was examined for amphetamine, methylphenidate, and its metabolite ritalinic acid.
Among the 9 patients who received D-amphetamine medication in daily doses of 20-100 mg, amphetamine was detected in all subjects in amounts ranging from 1200 to 30,800 picogram per filter. Among 8 patients receiving methylphenidate medication in daily doses of 80-400 mg, it was detected and quantified in 7 of the cases in amounts ranging from 150 to 10,400 picogram per filter and ritalinic acid was detected and quantified in 3 of the cases ranging from 35 to 360 picogram per filter. In 1 case, methylphenidate was only detectable in breath and urine, whereas ritalinic acid was quantifiable in urine, which could indicate noncompliance, with the 4 hours of dose regimen prescribed. In a number of cases, the sampling was performed 24 hours after the last dose intake. Identification of amphetamine and methylphenidate was based on correct chromatographic retention time and correct product ion ratio with detection performed in selected reaction monitoring mode.
The results confirm that amphetamine is present in exhaled breath after intake and demonstrate for the first time the presence of methylphenidate and ritalinic acid after its intake. This gives further support to the potential use of exhaled breath for detecting drug intake.
Therapeutic drug monitoring 01/2014; · 2.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A semi-automated method for quantification of budesonide in human plasma was developed, validated, and applied for high-volume analysis of samples in connection with a pharmacokinetic study. Protein and phospholipid removal was performed using an Ostro 96-well filter plate and subsequently combined with C18 solid-phase extraction on a Hamilton Microlab STARlet automation robot. The final extracts were evaporated to dryness and redissolved in 20% acetonitrile/water. The procedure used budesonide-d8 as internal standard and gave a 3.5-fold concentration of plasma to extract. The final extracts (5 μL injected) were analyzed with selected reaction monitoring liquid chromatography–tandem mass spectrometry (LC–MS/MS) using electrospray ionization in positive mode. The chromatography system used a 100 mm ACQUITY BEH UPLC column and a gradient system consisting of aqueous 0.1% formic acid and acetonitrile as organic modifier. Phospholipid removal was found to be needed during method development in order to reduce ion suppression effects from matrix and to increase method sensitivity. The measuring range was 50–5000 pg/mL with and LOD 24 pg/mL. Calibration response showed good linearity (correlation coefficients < 0.99) over the measuring range. The absolute recovery over the sample preparation procedure was estimated to 67%. Total imprecision was <9% at three levels and accuracy was between 98.9 and 103%. The method was successfully applied for analysis of 864 study samples in a short time. The quality control samples at concentration levels 200 and 2000 pg/mL gave a total imprecision of 7.4% and 4.2%, respectively, (n = 95).