Rapid Quantification of Buprenorphine-Glucuronide and Norbuprenorphine-Glucuronide in Human Urine by LC-MS-MS

Buprenorphine, Norbuprenorphine, and Naloxone Levels in Adulterated Urine Samples: Can They be Detected When Buprenorphine/Naloxone Film is Dipped into Urine or Water?

Reportedly, various urine manipulations can be performed by opioid use disorder (OUD) patients who are on buprenorphine/naloxone medications to disguise their non-compliance to the treatment. One type of manipulation is known as "spiking" adulteration, directly dipping a buprenorphine/naloxone film into urine. Identifying this type of urine manipulation has been the aim of many previous studies. These studies have revealed urine adulterations through inappropriately high levels of "buprenorphine" and "naloxone" and a very small amount of "norbuprenorphine." So, does the small amount of "norbuprenorphine" in the adulterated urine samples result from dipped buprenorphine/naloxone film, or is it a residual metabolite of buprenorphine in the patient's system? This pilot study utilized 12 urine samples from 12 participants, as well as water samples as a control. The samples were subdivided by the dipping area and time, as well as the temperature and concentration of urine samples, and each sublingual generic buprenorphine/naloxone film was dipped directly into the samples. Then, the levels of "buprenorphine," "norbuprenorphine," "naloxone," "buprenorphine-glucuronide" and "norbuprenorphine-glucuronide" were examined by Liquid Chromatography with tandem mass spectrometry (LC-MS/MS). The results of this study showed that high levels of "buprenorphine" and "naloxone" and a small amount of "norbuprenorphine" were detected in both urine and water samples when the buprenorphine/naloxone film was dipped directly into these samples. However, no "buprenorphine-glucuronide" or "norbuprenorphine-glucuronide" were detected in any of the samples. In addition, the area and timing of dipping altered "buprenorphine" and "naloxone" levels, but concentration and temperature did not. This study's findings could help providers interpret their patients' urine drug test results more accurately, which then allows them to monitor patient compliance and help them identify manipulation by examining patient urine test results.

Determination of buprenorphine, norbuprenorphine, naloxone, and their glucuronides in urine by liquid chromatography-tandem mass spectrometry

A liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of buprenorphine (BUP), norbuprenorphine (NBUP), naloxone (NAL), and their glucuronide conjugates BUP-G, NBUP-G, and NAL-G in urine samples was developed. The method, omitting a hydrolysis step, involved non-polar solid-phase extraction, liquid chromatography on a C18 column, electrospray positive ionization, and mass analysis by multiple reaction monitoring. Quantification was based on the corresponding deuterium-labelled internal standards for each of the six analytes. The limit of quantification was 0.5 μg/L for BUP and NAL, 1 μg/L for NAL-G, and 3 μg/L for NBUP, BUP-G, and NBUP-G. Using the developed method, 72 urine samples from buprenorphine-dependent patients were analysed to cover the concentration ranges encountered in a clinical setting. The median (maximum) concentration was 4.2 μg/L (102 μg/L) for BUP, 74.7 μg/L (580 μg/L) for NBUP, 0.9 μg/L (85.5 μg/L) for NAL, 159.5 μg/L (1370 μg/L) for BUP-G, 307.5 μg/L (1970 μg/L) for NBUP-G, and 79.6 μg/L (2310 μg/L) for NAL-G.

Determination of buprenorphine, naloxone and phase I and phase II metabolites in rat whole blood by LC-MS/MS

Buprenorphine and buprenorphine/naloxone combination are maintenance treatments used worldwide. However, since their marketing, despite ceiling respiratory effects, poisonings and fatalities have been attributed to buprenorphine misuse and overdose. Therefore, to better understand the mechanisms of buprenorphine-related toxicity in vivo, experimental investigations have been conducted, mainly in the rat. We developed a liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method with electrospray ionization for the simultaneous quantification of buprenorphine, naloxone and their metabolites (norbuprenorphine, buprenorphine glucuronide, norbuprenorphine glucuronide and naloxone glucuronide) in rat whole blood. Compounds were extracted from whole blood by protein precipitation and chromatographically separated using gradient elution of aqueous ammonium formate and methanol in a Raptor Biphenyl core-shell column (100 mm x 3,0 mm x 2,7 μm). Following electrospray ionization, quantification was carried out in the multiple reaction monitoring (MRM) mode by the tandem mass spectrometer API 3200 system. The LC-MS/MS method was validated according to the currently accepted criteria for bioanalytical method validation. The method required small sample volumes (50 μL) and was sensitive with limits of quantification of 6.9, 6.2, 3.6, 3.3, 1.3 and 57.7 ng/mL for buprenorphine, norbuprenorphine, buprenorphine glucuronide, norbuprenorphine glucuronide, naloxone and naloxone glucuronide respectively. The upper limit of quantification was 4000 ng/ml for all the studied compounds. Trueness (88-115 %), repeatability and intermediate precision (both <15%) were in accordance with the international recommendations. The procedure was successfully used to quantify these compounds in the whole blood sample from one rat 24 h after the intravenous administration of buprenorphine/naloxone (30.0/7.5 mg/kg).

High-sensitivity analysis of buprenorphine, norbuprenorphine, buprenorphine glucuronide, and norbuprenorphine glucuronide in plasma and urine by liquid chromatography-mass spectrometry

A new method using ultra-fast liquid chromatography and tandem mass spectrometry (UFLC-MS/MS) was developed for the simultaneous determination of buprenorphine and the metabolites norbuprenorphine, buprenorphine-3β-glucuronide, and norbuprenorphine-3β-glucuronide in plasma and urine. Sample handling, sample preparation and solid-phase extraction procedures were optimized for maximum analyte recovery. All four analytes of interest were quantified by positive ion electrospray ionization tandem mass spectrometry after solid-phase microextraction. The lower limits of quantification in plasma were 1pg/mL for buprenorphine and buprenorphine glucuronide, and 10pg/mL for norbuprenorphine and norbuprenorphine glucuronide. The lower limits of quantitation in urine were 10pg/mL for buprenorphine, norbuprenorphine and their glucuronides. Overall extraction recoveries ranged from 68-100% in both matrices. Interassay precision and accuracy was within 10% for all four analytes in plasma and within 15% in urine. The method was applicable to pharmacokinetic studies of low-dose buprenorphine.

Laboratory testing for prescription opioids

Opioid analgesic misuse has risen significantly over the past two decades, and these drugs now represent the most commonly abused class of prescription medications. They are a major cause of poisoning deaths in the USA exceeding heroin and cocaine. Laboratory testing plays a role in the detection of opioid misuse and the evaluation of patients with opioid intoxication. Laboratories use both immunoassay and chromatographic methods (e.g., liquid chromatography with mass spectrometry detection), often in combination, to yield high detection sensitivity and drug specificity. Testing methods for opioids originated in the workplace-testing arena and focused on detection of illicit heroin use. Analysis for a wide range of opioids is now required in the context of the prescription opioid epidemic. Testing methods have also been primarily based upon urine screening; however, methods for analyzing alternative samples such as saliva, sweat, and hair are available. Application of testing to monitor prescription opioid drug therapy is an increasingly important use of drug testing, and this area of testing introduces new interpretative challenges. In particular, drug metabolism may transform one clinically available opioid into another. The sensitivity of testing methods also varies considerably across the spectrum of opioid drugs. An understanding of opioid metabolism and method sensitivity towards different opioid drugs is therefore essential to effective use of these tests. Improved testing algorithms and more research into the effective use of drug testing in the clinical setting, particularly in pain medicine and substance abuse, are needed.

A sensitive, simple and rapid HPLC-MS/MS method for simultaneous quantification of buprenorpine and its N-dealkylated metabolite norbuprenorphine in human plasma

A sensitive, simple and rapid high performance liquid chromatography-tandem mass spectrometry (HPLC–MS/MS) method was developed and fully validated for the simultaneous quantification of buprenorphine (BUP) and its N-dealkylated metabolite norbuprenorphine (NBUP) in 200 μL human plasma. Human plasma samples were prepared using liquid–liquid extraction, and then separated on a Shiseido MG C18 (5 μm, 2.0 mm×50 mm) via 4.1 min gradient elution. Following electrospray ionization, the analytes were quantified on a triple–quadrupole mass spectrometer in multiple-reaction-monitoring (MRM) positive ion mode. Linearity was achieved from 25.0 to 10000 pg/mL for buprenorphine, from 20.0 to 8000 pg/mL for norbuprenorphine with r²>0.99. The method was demonstrated with acceptable accuracy, precision and specificity for the detection of buprenorphine and norbuprenorphine. Recovery was 81.8–88.8% for buprenorphine and 77.0–84.6% for norbuprenorphine, and the matrix effect was 95.6–97.4% for buprenorphine and 94.0–96.9% for norbuprenorphine; all were not concentration dependent. With validated matrix and autosampler stability data, this method was successfully applied in a bioequivalence study to support abbreviated new drug application.

¹³C labelled internal standards--a solution to minimize ion suppression effects in liquid chromatography-tandem mass spectrometry analyses of drugs in biological samples?

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is frequently used to identify and quantify drugs in human biological samples due to the high selectivity and sensitivity of this technique. However, ion suppression effects caused by co-eluting compounds: drugs, metabolites, matrix components, impurities and degradation products, are a major concern. Stable isotope labelled internal standards (SIL ISs), usually deuterium ((2)H) labelled, are often used to compensate for these effects. In many LC separations the retention times of (2)H labelled ISs and their analogues will differ. Ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) is increasingly being used for bio-analysis. With the better chromatographic resolution provided with sub 2 μm particles, larger separation between analytes and their (2)H labelled analogues can be expected, which might reduce the benefits of the SIL IS. There is a greater difference in physico-chemical properties between hydrogen isotopes than between isotopes of other elements. (13)C, (15)N and (18)O labelled ISs are more similar to their analytes than (2)H labelled ISs and thereby expected to behave more similarly in chromatographic separations. In this study we have investigated the use of (13)C and (2)H labelled ISs for the determination of amphetamine and methamphetamine by UPLC-MS/MS. The (13)C labelled ISs were co eluting with their analytes under different chromatographic conditions while the (2)H labelled ISs and their analytes were slightly separated. An improved ability to compensate for ion suppression effects were observed when the (13)C labelled ISs were used. Furthermore, an UPLC-MS/MS method for determination of amphetamine and methamphetamine in urine using (13)C labelled ISs has been developed and validated. Unfortunately, there are few (13)C labelled ISs commercial available today. If more (13)C labelled ISs become commercial available they may well be the coming solution to minimize ion suppression/enhancement effects in LC-MS/MS analyses of drugs in biological samples.

Issues pertaining to the analysis of buprenorphine and its metabolites by gas chromatography-mass spectrometry

"Substitution therapy" and the use of buprenorphine (B) as an agent for treating heroin addiction continue to gain acceptance and have recently been implemented in Taiwan. Mature and widely utilized gas chromatography-mass spectrometry (GC-MS) technology can complement the low cost and highly sensitive immunoassay (IA) approach to facilitate the implementation of analytical tasks supporting compliance monitoring and pharmacokinetic/pharmacogenetic studies. Issues critical to GC-MS analysis of B and norbuprenorphine (NB) (free and as glucuronides), including extraction, hydrolysis, derivatization, and quantitation approaches were studied, followed by comparing the resulting data against those derived from IA and two types of liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. Commercial solid-phase extraction devices, highly effective for recovering all metabolites, may not be suitable for the analysis of free B and NB; acetyl-derivatization products exhibit the most favorable chromatographic, ion intensity, and cross-contribution characteristics for GC-MS analysis. Evaluation of IA, GC-MS, and LC-MS/MS data obtained in three laboratories has proven the 2-aliquot GC-MS protocol effective for the determination of free B and NB and their glucuronides.

Confirmatory analysis of buprenorphine, norbuprenorphine, and glucuronide metabolites in plasma by LCMSMS. Application to umbilical cord plasma from buprenorphine-maintained pregnant women

An LCMSMS method was developed and fully validated for the simultaneous quantification of buprenorphine (BUP), norbuprenorphine (NBUP), buprenorphine-glucuronide (BUP-Gluc), and norbuprenorphine-glucuronide (NBUP-Gluc) in 0.5mL plasma, fulfilling confirmation criteria with two transitions for each compound with acceptable relative ion intensities. Transitions monitored were 468.3>396.2 and 468.3>414.3 for BUP, 414.3>340.1 and 414.3>326.0 for NBUP, 644.3>468.1 and 644.3>396.3 for BUP-Gluc, and 590.3>414.3 and 590.3>396.2 for NBUP-Gluc. Linearity was 0.1-50ng/mL for BUP and BUP-Gluc, and 0.5-50ng/mL for NBUP and NBUP-Gluc. Intra-day, inter-day, and total assay imprecision (%RSD) were <16.8%, and analytical recoveries were 88.6-108.7%. Extraction efficiencies ranged from 71.1 to 87.1%, and process efficiencies 48.7 to 127.7%. All compounds showed ion enhancement, except BUP-Gluc that demonstrated ion suppression: variation between 10 different blank plasma specimens was <9.1%. In six umbilical cord plasma specimens from opioid-dependent pregnant women receiving 14-24mg/day BUP, NBUP-Gluc was the predominant metabolite (29.8+/-7.6ng/mL), with BUP-Gluc (4.6+/-4.8ng/mL), NBUP (1.5+/-0.8ng/mL) and BUP (0.4+/-0.2ng/mL). Although BUP biomarkers can be quantified in umbilical cord plasma in low ng/mL concentrations, the significance of these data as predictors of neonatal outcomes is currently unknown.

Urinary excretion of buprenorphine, norbuprenorphine, buprenorphine-glucuronide, and norbuprenorphine-glucuronide in pregnant women receiving buprenorphine maintenance treatment

BACKGROUND

Buprenorphine (BUP) is under investigation as a medication therapy for opioid-dependent pregnant women. We investigated BUP and metabolite disposition in urine from women maintained on BUP during the second and third trimesters of pregnancy and postpartum.

METHODS

We measured BUP, norbuprenorphine (NBUP), buprenorphine glucuronide (BUP-Gluc), and NBUP-Gluc concentrations in 515 urine specimens collected thrice weekly from 9 women during pregnancy and postpartum. Specimens were analyzed using a fully validated liquid chromatography-mass spectrometry method with limits of quantification of 5 microg/L for BUP and BUP-Gluc and 25 microg/L for NBUP and its conjugated metabolite. We examined ratios of metabolites across trimesters and postpartum to identify possible changes in metabolism during pregnancy.

RESULTS

NBUP-Gluc was the primary metabolite identified in urine and exceeded BUP-Gluc concentrations in 99% of specimens. Whereas BUP-Gluc was identified in more specimens than NBUP, NBUP exceeded BUP-Gluc concentrations in 77.9% of specimens that contained both analytes. Among all participants, the mean BUP-Gluc:NBUP-Gluc ratio was significantly higher in the second trimester compared to the third trimester, and there were significant intrasubject differences between trimesters in 71% of participants. In 3 women, the percent daily dose excreted was higher during pregnancy than postpregnancy, consistent with other data indicating increased renal elimination of drugs during pregnancy.

CONCLUSIONS

These data are the first to evaluate urinary disposition of BUP and metabolites in a cohort of pregnant women. Variable BUP excretion during pregnancy may indicate metabolic changes requiring dose adjustment during later stages of gestation.

Simultaneous quantification of buprenorphine, norbuprenorphine, buprenorphine-glucuronide and norbuprenorphine-glucuronide in human umbilical cord by liquid chromatography tandem mass spectrometry

A LCMS method was developed and validated for the simultaneous determination of buprenorphine (BUP), norbuprenorphine (NBUP), buprenorphine-glucuronide (BUP-Gluc) and norbuprenorphine-glucuronide (NBUP-Gluc) in human umbilical cord. Quantification was achieved by selected ion monitoring of precursor ions m/z 468.4 for BUP; 414.3 for NBUP; 644.4 for BUP-Gluc and 590 for NBUP-Gluc. BUP and NBUP were identified by MS(2), with m/z 396, 414 and 426 for BUP, and m/z 340, 364 and 382 for NBUP. Glucuronide conjugates were identified by MS(3) with m/z 396 and 414 for BUP-Gluc and m/z 340 and 382 for NBUP-Gluc. The assay was linear 1-50 ng/g. Intra-day, inter-day and total assay imprecision (%RSD) were <14.5%, and analytical recovery ranged from 94.1% to 112.3% for all analytes. Extraction efficiencies were >66.3%, and process efficiency >73.4%. Matrix effect ranged, in absolute value, from 3.7% to 7.4% (CV<21.8%, n=8). The method was selective with no endogenous or exogenous interferences from 41 compounds evaluated. Sensitivity was high with limits of detection of 0.8 ng/g. In order to prove method applicability, an authentic umbilical cord obtained from an opioid-dependent pregnant woman receiving BUP pharmacotherapy was analyzed. Interestingly, BUP was not detected but concentrations of the other metabolites were NBUP-Gluc 13.4 ng/g, BUP-Gluc 3.5 ng/g and NBUP 1.2 ng/g.

Simultaneous quantification of buprenorphine, norbuprenorphine, buprenorphine glucuronide, and norbuprenorphine glucuronide in human placenta by liquid chromatography mass spectrometry

A LCMS method was developed and validated for the determination of buprenorphine (BUP), norbuprenorphine (NBUP), buprenorphine glucuronide (BUP-Gluc), and norbuprenorphine glucuronide (NBUP-Gluc) in placenta. Quantification was achieved by selected ion monitoring of m/z 468.4 (BUP), 414.3 (NBUP), 644.4 (BUP-Gluc), and 590 (NBUP-Gluc). BUP and NBUP were identified monitoring MS(2) fragments m/z 396, 414 and 426 for BUP, and 340, 364 and 382 for NBUP, and glucuronide conjugates monitoring MS(3) fragments m/z 396 and 414 for BUP-Gluc, and 340 and 382 for NBUP-Gluc. Linearity was 1-50 ng/g. Intra-day, inter-day and total assay imprecision (% RSD) were <13.4%, and analytical recoveries were 96.2-113.1%. Extraction efficiencies ranged from 40.7-68%, process efficiencies 38.8-70.5%, and matrix effect 1.3-15.4%. Limits of detection were 0.8 ng/g for all compounds. An authentic placenta from an opioid-dependent pregnant woman receiving BUP pharmacotherapy was analyzed. BUP was not detected but metabolite concentrations were NBUP-Gluc 46.6, NBUP 15.7 and BUP-Gluc 3.2 ng/g.

Development and validation of a liquid chromatography-tandem mass spectrometry assay for the simultaneous quantification of buprenorphine, norbuprenorphine, and metabolites in human urine

A liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of buprenorphine (BUP), norbuprenorphine (NBUP), buprenorphine glucuronide (BUP-Gluc), and norbuprenorphine glucuronide (NBUP-Gluc) in human urine was developed and fully validated. Extensive endogenous and exogenous interferences were evaluated and limits of quantification were identified empirically. Analytical ranges were 5-1,000 ng/mL for BUP and BUP-Gluc and 25-1,000 ng/mL for NBUP and NBUP-Gluc. Intra-assay and interassay imprecision were less than 17% and recovery was 93-116%. Analytes were stable at room temperature, at 4 degrees C, and for three freeze-thaw cycles. This accurate and precise assay has sufficient sensitivity and specificity for urine analysis of specimens collected from individuals treated with BUP for opioid dependence.

Validation and application of a method for the determination of buprenorphine, norbuprenorphine, and their glucuronide conjugates in human meconium

A novel liquid chromatography tandem mass spectrometry method for quantification of buprenorphine, norbuprenorphine, and glucuronidated conjugates was developed and validated. Analytes were extracted from meconium using buffer, concentrated by solid-phase extraction and quantified within 13.5 min. In order to determine free and total concentrations, specimens were analyzed with and without enzyme hydrolysis. Calibration was achieved by linear regression with a 1/x weighting factor and deuterated internal standards. All analytes were linear from 20 to 2000 ng/g with a correlation of determination of >0.98. Accuracy was >or=85.7% with intra-assay and interassay imprecision<or=13.9 and 12.4%, respectively. There was no interference from 70 licit and illicit drugs and metabolites. Buffer extraction followed by SPE yielded recoveries of >or=85.0%. There was suppression of ionization by the polar matrix; however, this did not interfere with sensitivity or analyte quantification due to inclusion of deuterated internal standards. Analytes were stable on the autosampler, at room temperature, at 4 degrees C, and when exposed to three freeze/thaw cycles. This sensitive and specific method can be used to monitor in utero buprenorphine exposure and to evaluate correlations, if any, between buprenorphine exposure and neonatal outcomes.