A liquid chromatography and tandem mass spectrometry method to determine 28 non-volatile drugs of abuse in exhaled breath.

Exhaled breath carries aerosol micro-particles containing nonvolatile organic substances. Recently, the analysis of drugs of abuse (DOA) have become of interest in exhaled breath particles (EBP). In this study, a liquid chromatography - tandem mass spectrometry (LC-MS/MS) method was developed and validated to analyze 28 DOA in 30L of EBP collected on a permeable polymer filter. After extraction, the chromatographic separation was achieved on a UPLC BEH phenyl column using a mobile phase consisting of methanol and water both containing 4mmol/L ammonium formate and 0.05% ammonia. The column temperature was set at 50°C and mobile phase flow rate 0.5mL/min in gradient mode with a total run time of 5min. The mass spectrometer was operated in positive electrospray ionization and selected reaction monitoring mode. Acquired limits of quantification were in the range of 1-66pg/filter for all substances except DM-tramadol. Excellent linearity over the concentration range from LLOQs - 15ng/filter with r2 values >0.99 and satisfactory recoveries (70-116% at 100pg/filter) were achieved. During method application a total 26 samples were analyzed of which 24 were found to be positive for 13 analytes. The highest amount was found for methadone (56ng/filter) and the lowest amount was found for the methadone metabolite EDDP (2pg/filter) in two different samples.

Two techniques to sample non-volatiles in breath-exemplified by methadone.

The particles in exhaled breath provide a promising matrix for the monitoring of pathological processes in the airways, and also allow exposure to exogenous compounds to be to assessed. The collection is easy to perform and is non-invasive. The aim of the present study is to assess if an exogenous compound-methadone-is distributed in the lining fluid of small airways, and to compare two methods for collecting methadone in particles in exhaled breath. Exhaled particles were collected from 13 subjects receiving methadone maintenance treatment. Two different sampling methods were applied: one based on electret filtration, potentially collecting exhaled particles of all sizes, and one based on impaction, collecting particles in the size range of 0.5-7 µm, known to reflect the respiratory tract lining fluid from the small airways. The collected samples were analyzed by liquid chromatography mass spectrometry, and the impact of different breathing patterns was also investigated. The potential contribution from the oral cavity was investigated by rinsing the mouth with a codeine solution, followed by codeine analysis of the collected exhaled particles by both sampling methods. The results showed that methadone was present in all samples using both methods, but when using the method based on impaction, the concentration of methadone in exhaled breath was less than 1% of the concentration collected by the method based on filtration. Optimizing the breathing pattern to retrieve particles from small airways did not increase the amount of exhaled methadone collected by the filtration method. The contamination from codeine present in the oral cavity was only detected in samples collected by the impaction method. We conclude that methadone is distributed in the respiratory tract lining fluid of small airways. The samples collected by the filtration method most likely contained a contribution from the upper airways/oral fluid in contrast to the impaction method.

Measurement of Lung Phosphatidylcholines in Exhaled Breath Particles by a Convenient Collection Procedure.

An analytical method based on high-performance liquid chromatography coupled to quadrupole tandem mass spectrometry was developed for the quantitative determination of four phosphatidylcholines (PCs) in human exhaled breath particles. Analytes were conveniently collected on an electrostatic polymer filter and extracted with methanol prior to analysis. Chromatographic separation was performed on an ultraperformance liquid chromatographic ethylene bridged hybrid phenyl column using a mobile phase consisting of water and methanol containing 4 mM ammonium formate and 0.1% ammonia. The mass spectrometer operated in positive electrospray ionization and selected reaction monitoring mode. Detection limits for PC 16:0/16:0 (dipalmitoylphosphatidylcholine, DPPC), PC 16:0/18:1, PC 16:0/18:2, and PC 18:0/18:2 were <0.01 ng/filter. Method recoveries at concentration levels of 0.1 and 10 ng/filter were 100-110% and 101-121%, respectively. Acceptable precision with coefficients of variation <20% and accuracies of 100% ± 20% were achieved. Identification of the individual PCs was performed on the basis of two product ions with correct ion ratios and chromatographic retention times. The highest amount in exhaled breath was found for DPPC with median concentration 1.14 ng/filter (range 0.6-21 ng/filter), and median molar ratios of DPPC/PC (16:0/18:1) of 1.98 (range 0.48-2.75). A different pattern with lower molar ratio (∼0.15) was found for oral fluid. The most significant element of this study was to use a precolumn in the LC system and to collecting exhaled particles in an electret polymer filter. Due to chromatographic interference by background contamination, an isolator column (PFC kit) was installed in between eluent mixer and injector to reduce contamination. This is the first LC/MS study where the method was successfully applied to analyze PCs in human exhaled breath by using a simple and convenient collection procedure.

Method validation and application of a liquid chromatography-tandem mass spectrometry method for drugs of abuse testing in exhaled breath.

A mass spectrometric method for drugs of abuse testing in exhaled breath employing a sampling device collecting aerosol particles was developed and applied in routine use. Analytes covered were amphetamine, methamphetamine, 6-acetylmorphine, morphine, cocaine, benzoylecgonine, diazepam, oxazepam and tetrahydrocannabinol. The method involved eluting drugs from the collection filter with methanol, quantification using deuterated analogs as internal standards, reversed phase chromatography with gradient elution, positive electrospray ionization and monitoring of two product ions per analyte in selected reaction monitoring mode. The measuring range was 6.0-1000pg/filter. The intra- and inter-assay imprecision expressed as the coefficient of variation was less than 7%. Influence from matrix was noted for most compounds but was compensated for the use of co-eluting internal standards. The LLOQ was 6.0pg/filter with intra-assay CV <5% and accuracy within 99-102% for all analytes. No chromatographic interference was observed in 20 negative control samples. The LC-MS/MS method was successfully applied for measuring drugs in unknown samples collected for the purpose of drug testing. Among the 1096 analyzed samples analytical findings were made in breath in 39 cases (3.6%). Most frequently found substances were the following: amphetamine (25 cases) methamphetamine (10 cases), THC (8 cases), cocaine (4 cases), benzoylecgonine (2 cases) and diazepam (2 cases). In conclusion, a fully validated and robust screening method suitable for the routine measurement of drugs of abuse in exhaled breath with a simple procedure for specimen collection and sample preparation was successfully developed.

Determination of amphetamine and methylphenidate in exhaled breath of patients undergoing attention-deficit/hyperactivity disorder treatment.

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Detection of drugs of abuse in exhaled breath using a device for rapid collection: comparison with plasma, urine and self-reporting in 47 drug users.

Exhaled breath has recently been identified as a matrix for the detection of drugs of abuse. This work aims to further document this application using a new and simple collection device in patients following recovery from acute intoxication. Breath, plasma and urine samples were collected from 47 patients (38 males, age range 25-74) together with interview data. Analysis of breath and plasma samples was done by liquid chromatography-mass spectrometry methods. Urine was screened using immunochemical reagents and positive findings confirmed with liquid chromatography-mass spectrometry methods. The 12 analytes investigated were: methadone, amphetamine, methamphetamine, 6-acetylmorphine, morphine, benzoylecgonine, cocaine, diazepam, oxazepam, alprazolam, buprenorphine and tetrahydrocannabinol. In all 47 cases, recent intake of an abused substance prior to admission was reported, but in one case the substance (ketobemidone) was not investigated. In 40 of the remaining cases (87%) breath analysis gave a positive finding of any of the substances that were part of the analytical investigation. Identifications were based on correct chromatographic retention time and product ion ratios obtained in selected reaction monitoring mode. In general, data from breath, plasma, urine and self-reporting were in good agreement, but in 23% of the cases substances were detected that had not been self-reported. All substances covered were detected in a number of breath samples. Considering that breath sampling was often done about 24 h after intake, the detection rate was considered to be high for most substances. Analytes with low detection rates were benzodiazepines, and a further increase in analytical sensitivity is needed to overcome this. This study further supports use of exhaled breath as a new matrix in clinical toxicology.

Detection of drugs of abuse in exhaled breath from users following recovery from intoxication.

It has recently been demonstrated that amphetamine, methadone and tetrahydrocannabinol are detectable in exhaled breath following intake. Exhaled breath, therefore, constitutes a new possible matrix for drugs-of-abuse testing. The present work aims to further explore this possibility by a study on patients treated for acute intoxication with abused drugs. Fifty-nine patients (44 males, age range 24-74) were included in the study, and breath, plasma and urine samples were collected following recovery, together with interview data. Analyses of breath and plasma samples were conducted with liquid chromatography-mass spectrometry methods. Urine was screened using immunochemical reagents and positive findings confirmed with liquid chromatography-mass spectrometry methods. The following analytes were investigated: methadone, amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, codeine, 6-acetylmorphine, diazepam, oxazepam, morphine, benzoylecgonine, cocaine, buprenorphine and tetrahydrocannabinol. In 53 of the studied cases, recent intake of an abused substance prior to admission was reported. In 35 of these (66%), the breath analysis gave a positive finding. Identifications were based on correct chromatographic retention time and product ion ratios obtained in selected reaction monitoring mode. Generally, data from breath, plasma, urine and self-report were in agreement. Detected substances in breath included amphetamine, methamphetamine, buprenorphine, 6-acetylmorphine, morphine, codeine, methadone, tetrahydrocannabinol, diazepam, oxazepam and cocaine. Problem analytes with low detection rates were benzodiazepines and tetrahydrocannabinol. This study gives further support to the possibility of developing exhaled breath into a new matrix for drugs-of-abuse testing by extending the number of analytes that are documented to be detectable in breath.

Detection of Δ9-tetrahydrocannabinol in exhaled breath collected from cannabis users.

Exhaled breath has recently been proposed as a new possible matrix for drugs of abuse testing. A key drug is cannabis, and the present study was aimed at investigating the possibility of detecting tetrahydrocannabinol and tetrahydrocannabinol carboxylic acid in exhaled breath after cannabis smoking. Exhaled breath was sampled from 10 regular cannabis users and 8 controls by directing the exhaled breath by suction through an Empore C(18) disk. The disk was extracted with hexane/ethyl acetate, and the resulting extract was evaporated to dryness and redissolved in 100 µL hexane/ethyl acetate. A 3-µL aliquot was injected onto the LC-MS-MS system and analyzed using positive electrospray ionization and selected reaction monitoring. In samples collected 1-12 h after cannabis smoking, tetrahydrocannabinol was detected in all 10 subjects. The rate of excretion was between 9.0 and 77.3 pg/min. Identification of tetrahydrocannabinol was based on correct retention time relative to tetrahydrocannabinol-d(3) and correct product ion ratio. In three samples, peaks were observed for tetrahydrocannabinol carboxylic acid, but these did not fulfill identification criteria. Neither tetrahydrocannabinol or tetrahydrocannabinol carboxylic acid was detected in the controls. These results confirm older reports that tetrahydrocannabinol is present in exhaled breath following cannabis smoking and extend the detection time from minutes to hours. The results further support the idea that exhaled breath is a promising matrix for drugs-of-abuse testing.

Demonstration that methadone is being present in the exhaled breath aerosol fraction.

Methadone has previously been found present in exhaled breath of methadone treated patients. This study aimed at studying if methadone is present in the aerosol fraction of exhaled breath and used different filter sampling techniques for that. Patients receiving methadone maintenance treatment were recruited for the study. Methadone was extracted from filters collecting methadone from exhaled breath using 2-propanol, methanol and ethyl acetate and measured using liquid-chromatography-tandem mass-spectrometry. The limit of quantification was 5 pg/sample and the intra-day imprecision and accuracy within 15%. The recovery of extracting methadone from filters was >90%. Two types of micro-particle filters were used in this study and were compared with the C18 silica filter (Empore) used before. The Glass fiber filter collected methadone from exhaled breath of methadone patients. The amount collected significantly exceeded the amount using the C18 Empore filter (3.6-14-fold), but the variability of amount trapped was large. The second filter type was a polymer filter. Also this filter was able to trap methadone from exhaled breath of methadone patients. The amount and variability was similar to the C18 Empore filter but smaller than the Glass fiber filter. The mean rate of methadone excretion measured with the best polymer filter was 92 pg/min with a range between 20 and 287 (n=5). The polymer filter has the practical advantage of having a low flow resistance making it possible to sample without pumping assistance. The polymer filter was found to collect >90% of the exhaled methadone. The conclusion of this study was that methadone in exhaled breath is carried in the aerosol fraction known to be formed in the lung as a result of normal breathing.

Study on the sampling of methadone from exhaled breath.

This study aimed at develop and validate the procedure for collecting exhaled breath for drug testing. Patients receiving methadone maintenance treatment were recruited for the study. Methadone levels were measured using liquid chromatography- electrospray-tandem mass spectrometry. The sampling device was based on a 47-mm C(18) filter and used under pressure to aid flow through the filter. The mouth was rinsed before sampling, and the device was constructed to protect against any saliva contamination. Methadone was present in breath samples before and after the daily intake of methadone. The mean (± SD) pre-dose level was found to be 135 ± 109 pg/min (n = 48, median 121). The exhaled methadone increased after dose intake. Saliva levels of methadone were high in comparison with exhaled breath levels. Saliva contamination was suspected in about 10% of the collected samples. Similar results were obtained using 1, 3, and 10 min sampling times. The inter- and intraindividual variability were found to be similar and in the order of 50%. Alternative sampling using XAD-2 beads and solid-phase microextraction fiber was found to be possible and enables sampling with low back pressure and with no need for pump assistance. The presented results confirm that breath testing is a new possibility for the detection of drugs of abuse.

Determination of methadone in exhaled breath condensate by liquid chromatography-tandem mass spectrometry.

Within the field of toxicology exhaled breath is used as specimen only for determination of alcohol. However, it was recently discovered that when using sensitive liquid chromatography-mass spectrometry (LC-MS) technique, amphetamine, methamphetamine, and methadone are detectable in exhaled breath following intake by drug addicts. We therefore undertook to develop a method for determination of methadone in exhaled breath condensate from patients undergoing methadonemaintenance treatment. Exhaled breath condensate was collected from 14 patients after intake of the daily methadone dose. The exhaled breath condensate was collected for 10 min using an Ecoscreen instrument. After extraction of any trapped methadone from the condensate by solid-phase extraction, the final extract was analyzed by a combined LC-MS-MS method. Recovery of methadone from breath condensate in the solid-phase extraction was 104%, no significant matrix effects were observed, and the quantification using methadone-d(3) as internal standard was accurate (10% bias) and precise (coefficient of variation 6.2%). Methadone was indisputably identified by means of the MS technique in exhaled breath condensate from all 14 patients. Identification was based on monitoring two product ions in selected reaction monitoring mode with correct relative ratio (± 20%) and correct retention time. Excretion rates ranged from 23.6 to 275 pg/min. No methadone was detected in five control subjects (< 2 pg/min). This finding confirms that methadone is present in exhaled breath from patients in methadone treatment. Collection of exhaled breath specimen is likely to be complementary to other matrices presently in use in testing for drugs-of-abuse.

Method for determination of methadone in exhaled breath collected from subjects undergoing methadone maintenance treatment.

At present drugs of abuse testing using exhaled breath as specimen is only possible for alcohol. However, we recently discovered that using modern liquid chromatography-mass spectrometry technique amphetamine and methamphetamine is detectable in exhaled breath following intake in drug addicts. We therefore undertook to develop a method for determination of methadone in exhaled breath from patients undergoing methadone maintenance treatment. Exhaled breath was collected from 13 patients after intake of the daily methadone dose. The compounds were trapped by filtering the air through a C18 modified silica surface. After elution of any trapped methadone the extract was analysed by a combined liquid chromatography-tandem mass spectrometry method. Recovery of trapped methadone from the filter surface was 96%, no significant matrix effect was observed, and the quantification using methadone-d3 as an internal standard was accurate (<10% bias) and precise (coefficient of variation 1.6-2.0%). Methadone was indisputably identified by means of the mass spectrometry technique in exhaled breath samples from all 13 patients. Identification was based on monitoring two product ions in selected reaction monitoring mode with correct relative ratio (+/-20%) and correct retention time. Excretion rates ranged from 0.39 to 78ng/min. No methadone was detected in 10 control subjects. This finding confirms that breath testing is a new possibility for drugs of abuse testing. Collection of exhaled breath specimen is likely to be more convenient and safe as compared to other matrices presently in use.