Buprenorphine and Norbuprenorphine Concentrations in Human Breast Milk Samples Determined by Liquid Chromatography-Tandem Mass Spectrometry

Drugs in Human Milk Part 1: Practical and Analytical Considerations in Measuring Drugs and Metabolites in Human Milk

Human milk is a remarkable biofluid that provides essential nutrients and immune protection to newborns. Breastfeeding women consuming medications could pass the drug through their milk to neonates. Drugs can be transferred to human milk by passive diffusion or active transport. The physicochemical properties of the drug largely impact the extent of drug transfer into human milk. A comprehensive understanding of the physiology of human milk formation, composition of milk, mechanisms of drug transfer, and factors influencing drug transfer into human milk is critical for appropriate selection and use of medications in lactating women. Quantification of drugs in the milk is essential for assessing the safety of pharmacotherapy during lactation. This can be achieved by developing specific, sensitive, and reproducible analytical methods using techniques such as liquid chromatography coupled with mass spectrometry. The present review briefly discusses the physiology of human milk formation, composition of human milk, mechanisms of drug transfer into human milk, and factors influencing transfer of drugs from blood to milk. We further expand upon and critically evaluate the existing analytical approaches/assays used for the quantification of drugs in human milk.

Maternal care behavior and physiology moderate offspring outcomes following gestational exposure to opioids

The opioid epidemic has resulted in a drastic increase in gestational exposure to opioids. Opioid-dependent pregnant women are typically prescribed medications for opioid use disorders ("MOUD"; e.g., buprenorphine [BUP]) to mitigate the harmful effects of abused opioids. However, the consequences of exposure to synthetic opioids, particularly BUP, during gestation on fetal neurodevelopment and long-term outcomes are poorly understood. Further, despite the known adverse effects of opioids on maternal care, many preclinical and clinical studies investigating the effects of gestational opioid exposure on offspring outcomes fail to report on maternal care behaviors. Considering that offspring outcomes are heavily dependent upon the quality of maternal care, it is important to evaluate the effects of gestational opioid exposure in the context of the mother-infant dyad. This review compares offspring outcomes after prenatal opioid exposure and after reduced maternal care and integrates this information to potentially identify common underlying mechanisms. We explore whether adverse outcomes after gestational BUP exposure are due to direct effects of opioids in utero, deficits in maternal care, or a combination of both factors. Finally, suggestions for improving preclinical models of prenatal opioid exposure are provided to promote more translational studies that can help to improve clinical outcomes for opioid-dependent mothers.

Harmful effects of opioid use in pregnancy: A scientific review commissioned by the European Board and College of obstetrics and gynaecology (EBCOG)

Caring for pregnant women who have a recreational opioid use disorder is a common clinical challenge in modern obstetric care. These are an elusive population who often have multiple social issues that complicate their pregnancy management. Comprehensive and supportive maternal care can motivate these mothers to change her lifestyle. Multidisciplinary non-judgemental approach with appropriate medication and management, can result in good pregnancy outcomes for mother and her baby.

Approach to buprenorphine use for opioid withdrawal treatment in the emergency setting

INTRODUCTION

Opioid use disorder (OUD) is increasing in prevalence throughout the world, with approximately three million individuals in the United States affected. Buprenorphine is a medication designed, researched, and effectively used to assist in OUD recovery.

OBJECTIVE

This narrative review discusses an approach to initiating buprenorphine in the emergency department (ED) for opioid-abuse recovery.

DISCUSSION

Buprenorphine is a partial mu-opioid receptor agonist with high affinity and low intrinsic activity. Buprenorphine's long half-life, high potency, and 'ceiling effect' for both euphoric sensation and adverse effects make it an optimal treatment alternative for patients presenting to the ED with opioid withdrawal. While most commonly provided as a sublingual film or tablet, buprenorphine can also be delivered via transbuccal, transdermal, subdermal (implant), subcutaneous, and parenteral routes. Prior to ED administration, caution is recommended to avoid precipitation of buprenorphine-induced opioid withdrawal. Following the evaluation of common opioid withdrawal symptoms, a step-by-step approach to buprenorphine can by utilized to reach a sustained withdrawal relief. A multimodal medication-assisted treatment (MAT) plan involving pharmacologic treatment, as well as counseling and behavioral therapy, is essential to maintaining opioid remission. Patients may be safely discharged with safe-use counseling, close outpatient follow-up, and return precautions for continued management of their OUD. Establishing a buprenorphine program in the ED involves a multifactorial approach to establish a pro-buprenorphine culture.

CONCLUSIONS

Buprenorphine is an evidence-based, safe, effective treatment option for OUD in an ED-setting. Though successfully utilized by many ED-based treatment programs, the stigma of 'replacing one opioid with another' remains a barrier. Evidence-based discussions on the safety and benefits of buprenorphine are essential to promoting a culture of acceptance and optimizing ED OUD treatment.

Maternal Buprenorphine Maintenance and Lactation

BACKGROUND

In addition to the well-known benefits of human milk and breastfeeding for the mother and infant, breastfeeding may mitigate neonatal abstinence syndrome severity in prenatally opioid-exposed infants. However, lack of conclusive data regarding the extent of the presence of buprenorphine and active metabolites in human milk makes the recommendation of breastfeeding for buprenorphine-maintained women difficult for many providers.

OBJECTIVE

This study seeks to determine the concentrations of buprenorphine and its active metabolites (norbuprenorphine, buprenorphine-glucuronide, and norbuprenorphine-glucuronide) in human milk, maternal plasma, and infant plasma of buprenorphine-maintained women and their infants.

METHODS

Up to 10 buprenorphine-maintained women provided paired breast milk and plasma samples at 2, 3, 4, 14, and 30 days postdelivery, and 9 infants provided plasma samples on day 14 of life. All samples were analyzed via liquid chromatography tandem mass spectrometry to determine concentrations of buprenorphine, norbuprenorphine, buprenorphine-glucuronide, and norbuprenorphine-glucuronide by a fully validated method.

RESULTS

Concentrations of buprenorphine and metabolites are low in human milk and maternal plasma. Breastfed infant plasma concentrations of buprenorphine were low or undetectable and metabolite concentrations undetectable at 14 days of infant age. There were significant correlations between maternal buprenorphine dose and maternal plasma and human milk buprenorphine concentrations.

CONCLUSION

These data find low concentrations of buprenorphine and metabolites in human milk and lend support to the recommendation for lactation among stable buprenorphine-maintained women. However, the correlation between maternal dose and maternal plasma and human milk buprenorphine concentrations bears further study.

Bioanalytical challenge: A review of environmental and pharmaceuticals contaminants in human milk

An overview of bioanalytical methods for the determination of environmental and pharmaceutical contaminants in human milk is presented. The exposure of children to these contaminants through lactation has been widely investigated. The human milk contains diverse proteins, lipids, and carbohydrates and the concentration of these components is drastically altered during the lactation period providing a high degree of an analytical challenge. Sample collection and pretreatment are still considered the Achilles' heel. This review presents liquid chromatographic methods developed in the last 10 years for this complex matrix with focuses in the extraction and quantification steps. Green sample preparation protocols have been emphasized.

Simultaneous determination of buprenorphine, norbuprenorphine and naloxone in human plasma by liquid chromatography/tandem mass spectrometry

A simple, sensitive and rapid liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated for simultaneous quantification of naloxone, buprenorphine and its metabolite norbuprenorphine in human plasma. Human plasma samples were extracted using a single step liquid-liquid extraction, and then separated on an Imtakt Unison UK-C18 column (2.1×50mm, 3μm) using alkaline mobile phases with gradient elution. All of the analytes were detected in positive ion mode using multiple reaction monitoring (MRM). The method was validated and the specificity, linearity, lower limit of quantitation, precision, accuracy, recoveries and stability were determined. The linear range was 20-10000pg/mL for buprenorphine and norbuprenorphine; and 1-500pg/mL for naloxone. The correlation coefficient (R(2)) values for all three analytes were ≥0.995. The precision and accuracy for intra-day and inter-day were <11.0%. The recoveries were >63% and matrix effects were tracked by the deuterated internal standards (IS) with the IS-normalized matrix factor ranging from 0.96 to 1.33 for all three analytes. The validated method was successfully applied in a clinical pharmacokinetic study with low dose administration of sublingual buprenorphine and naloxone.

ABM clinical protocol #21: guidelines for breastfeeding and substance use or substance use disorder, revised 2015

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Buprenorphine for the treatment of opioid dependence in pregnancy

The treatment of opioid dependence during pregnancy has historically consisted of either medication-assisted withdrawal or maintenance treatment with methadone. Buprenorphine maintenance treatment is emerging as a treatment during pregnancy with distinct benefits for the neonate and the pregnant woman. Buprenorphine is effective in decreasing the risk of relapse in pregnant women. In addition, prenatal use of buprenorphine appears to decrease the severity and duration of neonatal abstinence syndrome as compared with methadone maintenance. Management of buprenorphine includes initiation and maintenance treatment as well as careful planning for pain control during and after delivery and prevention of postpartum relapse risk. Only very small amounts of buprenorphine enter breast milk, making it a good option for those who elect to breast-feed. There is evidence that emerging collaborative care models are effective ways to deliver buprenorphine maintenance treatment, although more investigation is needed to generalize this to the obstetric setting.

The wellbeing of infants exposed to buprenorphine via breast milk at 4 weeks of age

BACKGROUND

Buprenorphine has been available in Australia since 2000 as an alternative pharmacotherapy to methadone for the treatment of opioid dependence. However, there is little information in the literature regarding the effect of buprenorphine on the wellbeing of infants exposed to buprenorphine via breast milk, following discharge from hospital.

OBJECTIVE

The aim of the present study was to examine the wellbeing of infants exposed to buprenorphine via breast milk up to 4 weeks postnatally.

METHODS

Approximately 4 weeks after birth, information on the feeding and sleeping patterns, skin color, infant elimination patterns and hydration, and Neonatal Abstinence Scores of infants (n = 7) exposed to buprenorphine via breast milk was collected via both observation and documentation.

RESULTS

Infants were progressing well, with normal sleep patterns and skin color, and 2 mothers had minor concerns regarding infant elimination patterns. Four infants were exclusively breastfed and 3 were receiving a supplement, with a range of 260 to 700 mL of formula over 24 hours. The sleep patterns following feeding ranged from 1.55 to 3.33 hours, with a median of 2.12 hours.

CONCLUSION

No adverse effects were detected in infants exposed to buprenorphine via breast milk up to 4 weeks postnatally. Further research using larger samples to assess possible developmental effects over longer periods of time is required.

Breastfeeding rates and the relationship between breastfeeding and neonatal abstinence syndrome in women maintained on buprenorphine during pregnancy

INTRODUCTION

Although a growing body of evidence suggests that buprenorphine is a safe alternative to methadone in the treatment of opioid-dependent pregnant women, little is known about breastfeeding in this population. The first objective of this study was to describe breastfeeding rates among opioid-dependent pregnant women maintained on buprenorphine in an integrated medical and behavioral health program. The second objective was to determine whether breastfeeding is related to the duration, severity, and frequency of pharmacologic treatment for neonatal abstinence syndrome (NAS).

METHODS

A retrospective chart review was conducted for all infants born to opioid-dependent pregnant women treated in the integrated buprenorphine program between December 2007 and August 2012.

RESULTS

Eighty-five maternal-infant pairs were identified. Sixty-five women (76%) chose to breastfeed their infants after birth; of the women who initiated breastfeeding in the hospital, 66% were still breastfeeding 6 to 8 weeks postpartum. Although the data suggest that infants who were breastfed had less severe NAS (mean peak NAS, 8.83 vs 9.65 on a modified Finnegan Scoring System) and were less likely to require pharmacologic treatment (23.1% vs 30.0%) than infants who were not breastfed, these results were not statistically significant.

DISCUSSION

More than three-quarters of the opioid-dependent pregnant women in this case series chose to breastfeed after birth. Although a direct comparison of care models is not possible, the integrated model of care potentially reduced some of the barriers to breastfeeding as the women accessed all their care in a single, infant-friendly setting. Further work is needed to definitively determine whether breastfeeding mitigates NAS.

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.

ABM clinical protocol #15: analgesia and anesthesia for the breastfeeding mother, revised 2012

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Buprenorphine treatment of opioid-dependent pregnant women: a comprehensive review

AIMS

This paper reviews the published literature regarding outcomes following maternal treatment with buprenorphine in five areas: maternal efficacy, fetal effects, neonatal effects, effects on breast milk and longer-term developmental effects.

METHODS

Within each outcome area, findings are summarized first for the three randomized clinical trials and then for the 44 non-randomized studies (i.e. prospective studies, case reports and series and retrospective chart reviews), only 28 of which involve independent samples.

RESULTS

Results indicate that maternal treatment with buprenorphine has comparable efficacy to methadone, although difficulties may exist with current buprenorphine induction methods. The available fetal data suggest buprenorphine results in less physiological suppression of fetal heart rate and movements than methadone. Regarding neonatal effects, perhaps the single definitive conclusion is that prenatal buprenorphine treatment results in a clinically significant less severe neonatal abstinence syndrome (NAS) than treatment with methadone. The limited research suggests that, like methadone, buprenorphine is compatible with breastfeeding. Data available thus far suggest that there are no deleterious effects of in utero buprenorphine exposure on infant development.

CONCLUSIONS

While buprenorphine produces a less severe neonatal abstinence syndrome than methadone, both methadone and buprenorphine are important parts of a complete comprehensive treatment approach for opioid-dependent pregnant women.

Pharmacologic management of the opioid neonatal abstinence syndrome

Opioid use in pregnant women has increased over the last decade. Following birth, infants with in utero exposure demonstrate signs and symptoms of withdrawal known as the neonatal abstinence syndrome (NAS). Infants express a spectrum of disease, with most requiring the administration of pharmacologic therapy to ensure proper growth and development. Treatment often involves prolonged hospitalization. There is a general lack of high-quality clinical trial data to guide optimal therapy, and significant heterogeneity in treatment approaches. Emerging trends in the treatment of infants with NAS include the use of sublingual buprenorphine, transition to outpatient therapy, and pharmacogenetic risk stratification.

Estimated dose exposure of the neonate to buprenorphine and its metabolite norbuprenorphine via breastmilk during maternal buprenorphine substitution treatment

OBJECTIVE

The aim of the present study was to estimate the dose of buprenorphine and its primary metabolite norbuprenorphine that a breastfed infant would receive during maternal maintenance treatment with buprenorphine.

STUDY DESIGN

Seven pregnant opioid-dependent women taking buprenorphine (median, 7 mg/day; range, 2.4-24 mg) and who intended to breastfeed were recruited. After lactation was established, several milk samples were collected from each subject over a 24-hour dose interval, and buprenorphine and norbuprenorphine concentrations were measured by liquid chromatography-tandem mass spectrometry. The average concentration (C(avg)) across the dose interval was estimated as for both buprenorphine and norbuprenorphine (as buprenorphine equivalents). Absolute infant dose (AID), defined as C(avg) × daily milk intake, and relative infant dose (RID), defined as 100×AID/weight-adjusted maternal daily dose, via milk were calculated, assuming a milk intake of 0.15 L/kg/day. The infant's health and progress were assessed directly and by questionnaire on the study day.

RESULTS

Mean (95% confidence interval) norbuprenorphine concentration in milk and AID values (1.94 [0.79-3.08] μg/L and 0.29 [0.12-0.46] μg/kg/day, respectively) were approximately half those for buprenorphine (3.65[1.61-5.7] μg/L and 0.55 [0.24-0.85] μg/kg/day, respectively). Similarly, the mean RID values were 0.18% (0.11-0.25%) for norbuprenorphine and 0.38% (0.23-0.53%) for buprenorphine. The breastfed infants showed no adverse effects, were all in good health, and were progressing as expected.

CONCLUSION

Thus the dose of buprenorphine and norbuprenorphine received via milk is unlikely to cause any acute adverse effects in the breastfed infant.

Opioid dependent and pregnant: what are the best options for mothers and neonates?

Pregnancy in opioid-dependent women is a major public health issue. Women who are afflicted by opioid addiction are a highly vulnerable group of patients frequently becoming pregnant unplanned and at risk of adverse pregnancy outcomes and peri-natal complications. Opioid agonist maintenance treatment is the best option for the majority of women. Ideally, early and closely monitored treatment in an interdisciplinary team approach including social workers, nurses, psychologists, psychiatrists, gynecologists, anesthesiologists, and pediatricians should be provided. The treatment of comorbid psychiatric conditions, the resolution of financial, legal, and housing issues, and the psychosocial support provided have a significant effect on optimizing pregnancy outcomes. This paper aims to update health professionals in the field of gynecology and obstetrics on the latest optimal treatment approaches for mothers suffering from opioid dependence and their neonates.

Management of women treated with buprenorphine during pregnancy

The management of pregnancy and delivery of a woman on opiate-substitution therapy with buprenorphine requires a coordinated team approach by social services, addiction medicine, obstetrics, and pediatrics. Her obstetrical care is further complicated by the unique pharmacology of buprenorphine and the issues of pain management. Obstetrical providers should be familiar with the complex issues surrounding the optimal care of these women.

Buprenorphine for the treatment of perinatal opioid dependence: pharmacology and implications for antepartum, intrapartum, and postpartum care

Opioid dependence during pregnancy is associated with significant health risks for both the mother and her fetus. Opioid maintenance therapy with methadone (Dolophine) is the current standard of care, reduces medical and social risks associated with illicit drug use, and decreases rates of prematurity and low birth weight. However, treatment with methadone is frequently associated with neonatal abstinence syndrome. Buprenorphine is an alternative to methadone that preliminary data indicates is equivalent in safety and efficacy to methadone and significantly increases access to treatment. The pharmacology of buprenorphine and its implications for the care of pregnant women with opioid dependence are described.

Development and validation of a method for the determination of buprenorphine and norbuprenorphine in breast milk by gas chromatography-mass spectrometry

Buprenorphine (BUP) is used for the maintenance of opioid-addicted pregnant women. Because BUP and its main metabolite nor-BUP are excreted into breast milk, a sensitive and specific GC/MS method has been developed, optimized and validated for their determination in breast milk. BUP-d4 was used as internal standard. The sample preparation includes combination of protein precipitation with solid-phase extraction and derivatization (acetylation). The absolute recovery for both analytes was found to be higher than 87.3%. The limits of detection and quantification were 0.07 and 0.20 µg/L, respectively. The calibration curves were linear within the dynamic range 0.20-20.0 µg/L, with a correlation coefficient higher than 0.996. Intra- and inter-day accuracies were ranged from -7.06 to 4.50 and from -5.88 to 7.00%, respectively, while intra- and inter-day precision were less than 5.7 and 6.1%. The analytes were found to be stable in breast milk at 4 °C for one week, at -20 °C for one month, and after three freeze-thaw cycles. The method can be used for the determination of BUP and nor-BUP in breast milk of BUP-maintained mothers, in order to calculate the amount of drug that could pass to the newborn via breast milk and to avoid toxic consequences of breastfeeding.

Bioanalytical procedures and recent developments in the determination of opiates/opioids in human biological samples

The use and abuse of illegal drugs affects all modern societies, and therefore the assessment of drug exposure is an important task that needs to be accomplished. For this reason, the reliable determination of these drugs and their metabolites in biological specimens is an issue of utmost relevance for both clinical and forensic toxicology laboratories in their fields of expertise, including in utero drug exposure, driving under the influence of drugs and drug use in workplace scenarios. Most of the confirmatory analyses for abused drugs in biological samples are performed by gas chromatographic-mass spectrometric methods, but use of the more recent and sensitive liquid chromatography-(tandem) mass spectrometry technology is increasing dramatically. This article reviews recently published articles that describe procedures for the detection of opiates in the most commonly used human biological matrices, blood and urine, and also in unconventional ones, e.g. oral fluid, hair, and meconium. Special attention will be paid to sample preparation and chromatographic analysis.

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.

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.

ABM clinical protocol #21: Guidelines for breastfeeding and the drug-dependent woman

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Transfer of buprenorphine into breast milk and calculation of infant drug dose

Little is known about the safety of buprenorphine (BUP) in breastfeeding. The aim of this work was to investigate the transfer of buprenorphine and its main active metabolite, norbuprenorphine (n-BUP), into human milk and to determine the drug dose and effects in exposed infants. Seven lactating women, who were maintained on BUP treatment because of previous opiate addiction, were studied in an open observational study. All mothers had a strong wish to breastfeed their newborn infants. Buprenorphine samples for analysis were collected from the urine of 6 infants together with breast milk, blood, and urine from their mothers during a 24-hour period in the week after birth. One mother-infant pair was studied at 9 months of age. Buprenorphine and n-BUP were analyzed by a liquid chromatography/mass spectrometry method suitable for handling different matrices. Buprenorphine and n-BUP were found in low levels in the infants' urine. Breastfed infants were exposed to a calculated BUP dose per kg bodyweight less than 1%, with an average milk/plasma area under the curve of 1.7 (range, 1.1-2.8) for BUP and 0.7 (range, 0.4-1.2) for n-BUP. These data support the use of BUP during breastfeeding. However, the authors recommend that infants be monitored closely.

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.

Effect of psychotropic medication on the in vitro metabolism of buprenorphine in human cDNA-expressed cytochrome P450 enzymes

OBJECTIVE

The aim of the present study was to estimate the drug interaction potential of psychtropic medication on buprenorphine (BUP) N-dealkylation using cDNA-expressed cytochrome P450 (CYP) enzymes.

METHODS

BUP was incubated with psychotropic drugs and cDNA-expressed CYP 3A4 and CYP 2C8 enzymes. Seven substances were screened for their inhibition potency. To check for a mechanism-based component in inhibition, all substances were tested with and without preincubation, respectively. Norbuprenorphine (NBUP) concentrations were determined by liquid chromatography/tandem mass spectrometry, following liquid/liquid extraction.

RESULTS

Midazolam and zolpidem demonstrated greatest inhibition in screening experiments. As expected, IC(50) values without preincubation were higher than those after 30-min preincubation, with zolpidem 113.1 microM and midazolam 20.25 microM. Following a 30-min preincubation period in the absence of the probe substrate BUP, the apparent IC(50) values for zolpidem and midazolam were 20.17 microM and 3.5 microM.

CONCLUSION

Both midazolam and zolpidem showed a distinct inhibitory potency towards NBUP formation by CYP 3A4, implicating a decreased conversion of BUP. When preincubated, the inhibitory potency was increased, which strongly suggests a metabolically activated component in inhibition.

Potentials of ion trap collisional spectrometry for liquid chromatography/electrospray ionization tandem mass spectrometry determination of buprenorphine and nor-buprenorphine in urine, blood and hair samples

A liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method has been developed for the analysis of buprenorphine (BUP) and nor-buprenorphine (NBUP) in biological fluids. Analytes are isolated from urine and blood, after addition of d4-buprenorphine (d4-BUP) as internal standard, by solid-phase extraction. Preparation of hair involves external decontamination, mechanical pulverization, overnight incubation in acidic medium, and neutralization prior to extraction. Enzymatic hydrolysis with beta-glucuronidase may be performed to distinguish between free and total BUP. Chromatographic separation is accomplished by gradient elution on a cyanopropyl 2.1 x 150 mm column. Positive ion ESI and MS analyses are carried out in an ion trap mass spectrometer. The use of this mass analyzer allows effective collisional experiments to be performed on ESI-generated MH+ species. Abundant product ions are produced, which can be monitored together with precursor ions without losing sensitivity. Thus, assay selectivity is definitely increased with respect to LC/ESI-MS/MS methods in which only precursor ions are monitored. The method has good linearity (calibration curves were linear in the range 0.1-10 ng/mL in urine and blood, in the range 10-160 pg/mg in hair) and limits of detection of 0.05 ng/mL for both BUP and NBUP in blood and urine samples, of 4 pg/mg for both analytes in hair. Both intra- and inter-assay precision and accuracy were satisfactory at three concentrations studied: relative standard deviations were <13.7% in urine, <17.3% in blood, <17.8% in hair; percent deviation of the mean from the true value was always <10.5% in urine and blood, <16.1% in hair. The method can be used to determine both analytes in the urine and hair of drug addicts on replacement therapy, and in post-mortem blood specimens when there is suspicion of drug-related death.