Investigation of buprenorphine-related deaths using urinary metabolite concentrations.

Quantitative analysis of postmortem urine, instead of blood, for buprenorphine and metabolites may provide additional evidence for the diagnosis of fatal buprenorphine poisoning. In this study, 247 autopsy urine samples, previously testing positive for buprenorphine or norbuprenorphine, were quantitatively reanalysed with a recently developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for unconjugated buprenorphine (BUP), norbuprenorphine (NBUP), naloxone (NAL), and their respective conjugated metabolites, buprenorphine glucuronide (BUPG), norbuprenorphine glucuronide (NBUPG), and naloxone glucuronide (NALG). The cases were divided, according to medical examiners' decision, to buprenorphine poisonings and other causes of death. The groups were compared for urinary concentrations and metabolite concentration ratios of the six analytes. All median concentrations were higher in the buprenorphine poisoning group. The median concentration of BUPG was significantly higher and the median metabolite ratios NBUP/BUP, NBUPG/BUPG, and NBUPtotal/BUPtotal were significantly lower in poisonings than in other causes of death. Naloxone-related concentrations and ratios were not significantly different between the groups.

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.

Urine is superior to oral fluid for detecting buprenorphine compliance in patients undergoing treatment for opioid addiction.

BACKGROUND: Buprenorphine (BUP) is commonly used in opioid agonist medication-assisted treatment (OA-MAT). Oral fluid (OF) is an attractive option for compliance monitoring during OA-MAT as collections are observed and evidence suggests that OF is less likely to be adulterated than urine (UR). However, the clinical and analytical performance of each matrix for monitoring BUP compliance has not been well studied. METHODS: We collected 260 paired OF and UR specimens. Concentrations of buprenorphine (BUP) and norbuprenorphine (NBUP) were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in each matrix. The glucuronide metabolites and naloxone concentrations were also measured in UR by LC-MS/MS. Medications were reviewed and UR creatinine concentrations were determined. RESULTS: 147/260 specimens (57%) were positive for BUP and/or metabolites in one or both matrices. BUP and/or metabolites were more likely to be detected in UR (p < 0.001). 1 OF specimen and 12 UR specimens were considered adulterated/substituted. The majority of patients prescribed BUP were positive for BUP in UR (97%) as opposed to OF (78%). The detection of undisclosed use approximately doubled in UR. CONCLUSIONS: UR is the preferred matrix for detecting both buprenorphine compliance and undisclosed use. Clinicians should consider the ease of collection, risk of adulteration and detection of illicit drug use when deciding on an appropriate matrix. If OF testing is clinically necessary, UR should be measured in conjunction with OF at least periodically to avoid false negative BUP results.

Urinary buprenorphine concentrations in patients treated with suboxone as determined by liquid chromatography-mass spectrometry and CEDIA immunoassay.

We report on the utility of urine total buprenorphine, total norbuprenorphine, and creatinine concentrations in patients treated with Suboxone (a formulation containing buprenorphine and naloxone), used increasingly for the maintenance or detoxification of patients dependent on opiates such as heroin or oxycodone. Patients received 8-24 mg/day buprenorphine. Two-hundred sixteen urine samples from 70 patients were analyzed for both total buprenorphine and total norbuprenorphine by liquid chromatography-mass spectrometry (LC-MS-MS). Buprenorphine concentrations in all 176 samples judged to be unadulterated averaged 164 ng/mL, with a standard deviation (SD) of 198 ng/mL. Nine samples (4.2%) had metabolite-parent drug ratios < 0.02, and 33 (15.3%) had no detectable buprenorphine. The metabolite/parent drug ratio in 166 samples had a range of 0.07-23.0 (mean = 4.52; SD = 3.97). Fifteen of 96 available urine samples (16.7%) had creatinine less than 20 mg/dL. We also found sample adulteration in 7 (7.3%) available samples. Using a 5 ng/mL urine buprenorphine cutoff, the sensitivity and specificity of the Microgenics homogeneous enzyme immunoassay versus LC-MS-MS were 100% and 87.5%, respectively. The 5 ng/mL cutoff Microgenics CEDIA buprenorphine assay results agreed analytically with LC-MS-MS in 97.9% of samples.

Self-identification of nonpharmaceutical fentanyl exposure following heroin overdose.

OBJECTIVE: To compare user self-identification of nonpharmaceutical fentanyl exposure with confirmatory urine drug testing in emergency department (ED) patients presenting after heroin overdose. METHODS: This was a cross-sectional study of adult ED patients who presented after a heroin overdose requiring naloxone administration. Participants provided verbal consent after which they were asked a series of questions regarding their knowledge, attitudes and beliefs toward heroin and nonpharmaceutical fentanyl. Participants also provided urine samples, which were analyzed using liquid chromatography coupled to quadrupole time-of-flight mass spectrometry to identify the presence of fentanyl, heroin metabolites, other clandestine opioids, common pharmaceuticals and drugs of abuse. RESULTS: Thirty participants were enrolled in the study period. Ten participants (33%) had never required naloxone for an overdose in the past, 20 participants (67%) reported recent abstinence, and 12 participants (40%) reported concomitant cocaine use. Naloxone was detected in all urine drug screens. Heroin or its metabolites were detected in almost all samples (93.3%), as were fentanyl (96.7%) and its metabolite, norfentanyl (93.3%). Acetylfentanyl was identified in nine samples (30%) while U-47700 was present in two samples (6.7%). Sixteen participants self-identified fentanyl in their heroin (sensitivity 55%); participants were inconsistent in their qualitative ability to identify fentanyl in heroin. CONCLUSIONS: Heroin users presenting to the ED after heroin overdose requiring naloxone are unable to accurately identify the presence of nonpharmaceutical fentanyl in heroin. Additionally, cutting edge drug testing methodologies identified fentanyl exposures in 96.7% of our patients, as well as unexpected clandestine opioids (like acetylfentanyl and U-47700).

High buprenorphine-related mortality is persistent in Finland.

Sublingual buprenorphine is used in opioid maintenance treatment but buprenorphine is also widely abused and causes fatal poisonings. The aim of this study was to investigate buprenorphine-positive fatalities in order to gain novel information on the magnitude and nature of buprenorphine abuse. All post-mortem toxicology cases positive for urinary buprenorphine, including fatal poisonings caused by buprenorphine and fatalities in which the cause of death was unrelated to buprenorphine, in the five year period of 2010-2014 in Finland were characterized according to urine buprenorphine and naloxone concentrations (n=775). Urine concentrations were used to assess which buprenorphine preparation had been used; mono-buprenorphine or a buprenorphine-naloxone combination, and whether they had been administered parenterally. In at least 28.8% of the buprenorphine-positive cases the drug had been administered parenterally. The majority of the parenteral users (68.6%) had taken mono-buprenorphine. Fatal poisoning was significantly more common among the identified parenteral users (65.5%) than among other users of buprenorphine products (45.3%). The proportion of buprenorphine-related poisoning was similar in identified parenteral users of mono-buprenorphine (68.6%) and buprenorphine-naloxone (64.1%). In nearly all of the fatal poisoningss the deceased had used other drugs and/or alcohol along with buprenorphine (98.7%). The median age of the deceased increased significantly over the study period, from 32 to 38 years. Our results show that there is ongoing parenteral abuse of both mono-buprenorphine and buprenorphine-naloxone combination. Parenteral users of buprenorphine put themselves into a great risk of fatal poisoning or other accidental injury death which is further exacerbated by the frequent poly-drug use.

Quantitation of Buprenorphine, Norbuprenorphine, Buprenorphine Glucuronide, Norbuprenorphine Glucuronide, and Naloxone in Urine by LC-MS/MS.

Buprenorphine is an opioid drug that has been used to treat opioid dependence on an outpatient basis, and is also prescribed for managing moderate to severe pain. Some formulations of buprenorphine also contain naloxone to discourage misuse. The major metabolite of buprenorphine is norbuprenorphine. Both compounds are pharmacologically active and both are extensively metabolized to their glucuronide conjugates, which are also active metabolites. Direct quantitation of the glucuronide conjugates in conjunction with free buprenorphine, norbuprenorphine, and naloxone in urine can distinguish compliance with prescribed therapy from specimen adulteration intended to mimic compliance with prescribed buprenorphine. This chapter quantitates buprenorphine, norbuprenorphine, their glucuronide conjugates and naloxone directly in urine by liquid chromatography tandem mass spectrometry (LC-MS/MS). Urine is pretreated with formic acid and undergoes solid phase extraction (SPE) prior to analysis by LC-MS/MS.

Determination of buprenorphine, norbuprenorphine and naloxone in fingernail clippings and urine of patients under opioid substitution therapy.

The aim of this study was to develop and validate a method for the determination of buprenorphine (BUP), norbuprenorphine (NBUP) and naloxone (NAL) in fingernails and urine samples collected from former heroin users under suboxone substitution therapy. The analytes were extracted by solid-liquid or solid-phase extraction and were analyzed by liquid chromatography-mass spectrometry. The validation of the analytical methods developed included linearity, recovery, accuracy, precision, ion suppression, sensitivity of interfaces and limits of determination and quantification. The validated methods were applied to samples from 46 individuals. The majority of the urine samples were positive for all analytes (93.5% for BUP, 95.7% for NBUP and 84.8% for NAL). In nails, a higher detection rate was observed for NBUP and BUP (89.1%), compared with NAL (10.9%). The median values of the NBUP/BUP and the NAL/BUP ratio were 2.5 and 0.3 in urine and 0.8 and 0.3 in nails, respectively. A statistically significant correlation was found between the BUP, NBUP and total BUP (BUP and NBUP) concentrations in urine and those in nails. A weak correlation was observed between the daily dose (mg/day) and total BUP (P = 0.069), or NBUP (P = 0.072) concentrations in urine. In contrast, a strong correlation was found between the total amount of BUP administered during the last 12 months and total BUP (P = 0.038), or NBUP (P = 0.023) concentrations in urine. Moreover urine BUP, NBUP and total BUP concentrations correlated significantly. Our study demonstrated successfully the application of the developed method for the determination of the three analytes in urine and nails.

Effects exerted by otilonium bromide administration on precipitated opioid withdrawal syndrome in rats.

An opioid withdrawal syndrome was induced in rats by repeated morphine administration and final naloxone injection. The withdrawal causes alteration of several physiological signs. The aim of the study was to prevent the altered physiological profiles by utilising otilonium bromide. Morphine was administered in three daily i.p. injections for 4 days at doses of 9, 16 and 25 mg/kg (1st day), 25, 25 and 50 mg/kg (2nd day), 50, 50 and 50 mg/kg (3rd day) and 50, 50 and 100 mg/kg (4th day). Naloxone was injected (30 mg/kg) i.p. 180 min after the last morphine injection. Otilonium bromide was administered orally at 0, 2, 4 and 8 mg/kg, 120 min before the naloxone administration. Signs like faecal and urine excretion, rectal temperature and pain threshold levels, salivation, jumping and wet dog shakes were affected in different ways. Notably the administration of otilonium bromide in rats receiving morphine together with naloxone decreased the intensity of certain withdrawal symptoms, such as excretion of faeces, wet dog shake behaviour, and elevated the nociceptive threshold values. The effects exhibited by otilonium bromide administration may be explained through its calcium antagonist activity interfering with a mechanism involved in the regulation of these previously mentioned withdrawal symptoms. The use of this drug is thus suggested as a possible control of some acute opioid withdrawal signs in heroin addicts.

Early use of naloxone in shock--a clinical trial.

Naloxone hydrochloride (N) 0.4-1.2 mg i.v. was administered during 10 episodes of shock (8 septic and 2 cardiogenic) in 9 adult patients. Shock was defined as systolic blood pressure (SBP) less than or equal to 90 mmHg and urine output less than 0.5 ml/h and signs and symptoms of hypoperfusion lasting for greater than or equal to 30 min, despite fluid loading to a CVP 5 cmH2O above baseline. N was given as early as 30 min after onset of shock and resulted in an increase of SBP from a mean of 75 +/- 10 to a mean of 130 +/- 25 mmHg maximum (P less than 0.01). Within 10-60 min urine output increased from 16 +/- 12 to 122 +/- 56 ml/h, heart rate, CVP and arterial blood gas tensions remained unchanged. No side effects were observed. Naloxone, even in small doses, may improve hemodynamic parameters in human shock, provided it is administered very early.

Electrochemical chromatographic determinations of morphine antagonists in biological fluids, with applications.

The morphine antagonists naltrexone and naloxone were extracted from plasma and urine, separated on a chromatographic column, and assayed by electrochemical detection. Optimum oxidation potentials were 0.65 V for morphine and 0.75 V for naloxone and naltrexone. Assay sensitivities were 2-5 ng/mL for plasma and 10 ng/mL for urine. The assays were applied to determine red blood cell partition coefficients of 1.83 +/- 0.15 (SD) for naltrexone and 1.49 +/- 0.27 (SD) for naloxone in a concentration range of 10-3500 ng/mL. No significant time dependence for the partitioning could be observed. Plasma protein binding in the same concentration range, determined by ultracentrifugation, was 27.7% +/- 2.5% (SD) for naltrexone and 30.1% +/- 5.1% (SD) for naloxone. The degree of protein binding did not change in the presence of morphine for morphine-antagonist ratios between 1:10 and 10:1. No concentration dependencies of red blood cell partitioning or protein binding were observed.

Improved method for morphine extraction from biological samples.

Methadone morphine, or naloxone extraction from brain homogenates, plasma, and urine is described. An aqueous sample was loaded on a surgical gauze support, which was washed with extracting solvents. Aqueous samples remained on the support, and nonpolar drugs partitioned into the lipophilic extracting solvent. The procedure recovered 80-100% of nanogram levels of methadone, morphine, or naloxone from biological samples. In addition, an approximate 10-fold timesaving capacity was demonstrated compared to standard liquid-liquid extraction techniques.

Biosynthesis, isolation, and identification of 6-beta-hydroxynaltrexone, a major human metabolite of naltrexone.

Chemical reduction of naltrexone is described in an attempt to synthesize 6-beta-hydroxynaltrexone. Only the epimer, 6-alpha-hydroxynaltrexone, was produced. Pilot metabolic studies on naltrexone in the dog, rat, and guinea pig were made to determine which animal produced the greatest amount of 6-beta-hydroxynaltrexone. The guinea pig was selected and used to produce the metabolite. Isolation and purification methods are described, and spectral data are presented for structural confirmation of the metabolite.

Long acting delivery systems for narcotic antagonists II: release rates of naltrexone from poly(lactic acid) composites.

Parallel in vitro and in vivo release rates of tritiated naltrexone from poly(lactic acid) composites were studied. The in vitro release of naltrexone was 67% of the dose over a 35-day test period, while the in vivo release was only 24% within 70 days. Apparently, an exchange of the tritium for the hydrogen of the body water takes place, indicating that urinary excretion radioactivity is not a reliable measure for estimating the naltrexone released. Naltrexone-poly(lactic acid) composites showed effective blocking action to morphine in rats (24 days), dogs (29 days), monkeys (20 days), and mice (21 days).

Urine naloxone concentration at different phases of buprenorphine maintenance treatment.

In spite of the benefits of buprenorphine-naloxone co-formulation (BNX) in opioid maintenance treatment, the naloxone component has not prevented parenteral use of BNX. Current laboratory methods are not sufficient to differentiate between therapeutic and illicit use of buprenorphine, and little is known about urine naloxone concentrations. Measurement of urine naloxone, together with buprenorphine and norbuprenorphine, might help to determine the naloxone source and administration route. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for this purpose. Naloxone, buprenorphine, and norbuprenorphine total concentrations were measured in urine samples from opioid-dependent patients before and during stable and unstable phases of maintenance treatment with BNX. The limit of quantification in urine was 1.0 µg/L for naloxone, buprenorphine and norbuprenorphine. Before treatment, all samples contained buprenorphine but the median naloxone concentration was 0 µg/L. During the maintenance treatment with BNX all urine samples were positive for naloxone, buprenorphine and norbuprenorphine. The naloxone concentration at a stable phase of treatment (median 60 µg/L, range 5-200 µg/L) was not different from the naloxone concentration at an unstable phase (70 µg/L, 10-1700 µg/L). Applying an upper limit of 200 µg/L to the sample, the median naloxone/buprenorphine ratio was higher in the high than in the low naloxone concentration group (0.9 vs 0.3, respectively). This study suggests that naloxone in urine can act as an indicator of compliance with BNX. Parenteral use of BNX was associated with a high naloxone/buprenorphine ratio. Negative naloxone with positive buprenorphine suggests the use/abuse of buprenorphine alone.

Determination of naloxone-3-glucuronide in human plasma and urine by HILIC-MS/MS.

A hydrophilic interaction chromatography-tandem mass spectrometric (HILIC-MS/MS) method was developed for the direct determination of naloxone-3-glucuronide (N3G) in human plasma and urine. After a straightforward sample preparation by protein precipitation, N3G was analyzed directly without the need for hydrolysis. Chromatographic separation was performed on a HILIC column. The mobile phase was composed of acetonitrile-10mmol/L ammonium formate (86:14, v/v), with a flow rate of 0.4mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode via positive electrospray ionisation (ESI+) source. The linear calibration range was 0.5 to 200ng/mL in plasma and 10 to 5000ng/mL in urine (r(2)>0.99). The intra- and inter-day precision (relative standard deviation, RSD) values were below 15% and the accuracies (relative error, RE) were -7.1% to 2.8% in plasma and -1.3% to 10.3% in urine at three quality control levels. In human subjects receiving 100mg tilidine and 8mg naloxone, mean AUC0-24 of N3G was 160.93±52.77ng/mLh and mean Cmax was 75.33±25.27ng/mL. In 24-h urine samples, 8.0% of the dose was excreted in the form of N3G in urine. These results demonstrated a new method suitable for in vivo pharmacokinetic studies of N3G.

Parenteral buprenorphine-naloxone abuse is a major cause of fatal buprenorphine-related poisoning.

Buprenorphine (BPN) medication for opioid maintenance treatment in Finland consists predominantly of buprenorphine-naloxone (BNX). Both BPN and BNX are associated with diversion, abuse and non-medically supervised use worldwide. Our purpose was to estimate the proportion of BNX to all BPN-related fatalities. The material consisted of 225 deceased drug abusers in Finland from January 2010 to June 2011 with a positive BPN and/or norbuprenorphine (NOR) and/or naloxone (NX) finding in urine. The data were divided into three groups based on the urine NX and BPN concentrations. The "Parenteral BNX" group (>100 µg/l NX) was presumed to consist of injecting or snorting BNX abusers and the "Parenteral BPN" group (>50 µg/l BPN, 0 µg/l NX) of injecting or snorting BPN abusers, while the "Other BNX or BPN" group (≤100 µg/l NX, or ≤50 µg/l BPN combined with 0 µg/l NX) was presumed to consist of mainly sublingual BNX or BPN users. In 12.4% of cases the NX urine concentration was higher than the threshold 100 µg/l. In fatal BPN poisonings, the proportion of parenteral BNX was 28.4%. In the "Parenteral BNX", "Parenteral BPN" and "Other BNX or BPN" groups, the proportion of fatal BPN poisonings was 67.9, 31.0 and 22.6%, respectively. BNX abuse can be fatal. Among the 225 BPN-related fatalities, parenteral abuse of BNX was shown to be common (12.4%) and BNX poisoning was the underlying cause of death in 8.4%. Parenteral BNX caused fatal BPN poisoning proportionally more often than parenteral BPN.