Concentrations Of Bupropion Research Articles

Temporal monitoring of pharmaceutical consumption using a wastewater-based epidemiologic approach

Temporal monitoring of antidepressants, opioids consumption through influent wastewater, before and during the COVID-19 pandemic in Leuven, Belgium. Introduction: Conventional epidemiologic data sources on pharmaceutical consumption include surveys, prescription, sales, and dispensing data. However, prescribed medication may not always be dispensed, and surveys are affected by bias (e.g., response, reporting). Furthermore, data on pharmaceutical dispensing in Belgium only covers public pharmacies, and only records reimbursed medication (e.g., over-the-counter medication, some opioids are unrecorded). In addition, patients may not take the dispensed drugs as prescribed, or incorrectly. There is also a long lag time such as three years for survey data, and over three months for dispensing data. Wastewater-based epidemiology (WBE) centres on the analysis of biomarkers, i.e., human metabolic excretion products of xenobiotics in influent wastewater. WBE complements existing drug utilisation approaches and provides valuable, objective, spatio-temporal information on the consumption of pharmaceuticals in the general population that may not be measured in other datasets. WBE was applied to 24-h composite influent wastewater samples from Leuven, Belgium. Daily samples were analysed from Sept 2019 to Dec 2019 ( n = 63), and on each Monday, Wednesday, and Saturday of the week from Jan 2020 to Dec 2021 ( n = 165). The sampled period also included several governmental restrictions (e.g., stay at home measures) to contain the spread of SARS-CoV-2. Sample preparation and analysis consisted of preconcentration with solid-phase extraction and liquid chromatography coupled to tandem mass spectrometry, respectively. Measured concentrations (ng/L) of 21 pharmaceutical biomarkers, i.e., parent compounds and metabolites, were converted to population normalised mass loads (PNML) by considering the flow rate and catchment population. To better capture population movements, mobile phone data was used in the back-calculations. Concentrations of bupropion, hydromorphone, melitracen, noroxycodone, oxycodone, and tilidine were negligible or below limit of quantification and therefore excluded from further analysis. The pharmaceuticals, amitriptyline, hydroxy-bupropion, N-desmethylcitalopram, citalopram, N-desmethyl-mirtazapine, mirtazapine, trazodone, O-desmethylvenlafaxine, codeine, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, methadone, morphine, nortilidine, O-desmethyltramadol, and tramadol were detected and included in the temporal assessment. The PNML of most psychoactive pharmaceuticals remained stable throughout the entire sampling period. Highest median PNML levels by pharmaceutical class, respectively opioid and antidepressant, were obtained for tramadol (median 508 mg/day/1000 people) and O-desmethylvenlafaxine (median 392 mg/day/1000 people). Governmental measures appear to have minimal effect on the consumption. Several studies have described the psychological distress (e.g., anxiety, stress) of these measures on mental health (COVID-19 Impact, Sciensano; Mental Health Considerations during COVID-19, WHO). However, there is a long lag time between onset of mental distress, help seeking, and the actual start of pharmaceutical therapy. The sampled period may need to be extended to detect this. It remains important to monitor psychoactive pharmaceuticals with addiction potential (e.g., opioids), as they have led to health crisis in other countries. Throughout the sampled period, a small difference in week/weekend PNML is observed for all analysed pharmaceuticals. Antidepressants and opioids are indicated to be used consistently, and long-term in case of antidepressants. We hypothesize that this change may be explained due to a change in population demographics. Leuven has a large commuting student population, approx. 45% of census population, although it should be noted that the catchment area also encompasses nearby areas. This study shows the potential of WBE to monitor consumption trends of pharmaceuticals with high temporal resolution, may not be captured by other data sources. Furthermore, our findings demonstrate that care should be taken when interpreting WBE results in case of large population disruption, such as a large commuting population or COVID-19 governmental measures.

Corrosion protection of carbon steel in acidic media by expired bupropion drug; experimental and theoretical study

The effects of expired bupropion on the corrosion protection of carbon steel in hydrochloric acid (1.0 M) and sulfuric acid (0.5 M) solutions were examined by Fourier transform infrared (FTIR) spectroscopy, Tafel polarization and electrochemical impedance spectroscopy (EIS). Bupropion concentrations in both acid solutions were raised, which improved corrosion prevention. Bupropion was a mixed inhibitor because it retarded the anodic and cathodic processes, as indicated by polarization data. The inhibition efficiency decreased with the increasing temperature from 25 to 55 °C. In the presence of bupropion, the activation energies of corrosion in both acid solutions increased. The thermodynamic quantities were deduced from the influence of temperature on the corrosion process of carbon steel in both acid media. Bupropion adsorption on carbon steel followed the Langmuir adsorption isotherm. The polarization data yielded outcomes consistent with the results arising from impedance measurements. FTIR spectroscopy showed the active sites of bupropion molecule during adsorption on the alloy surface. The theoretical study and molecular dynamics simulation of bupropion was done by a density functional theory (DFT) approach to realize the effects of molecular structure on the inhibitive action of bupropion.

A Bayesian population physiologically based pharmacokinetic absorption modeling approach to support generic drug development: application to bupropion hydrochloride oral dosage forms

We propose a Bayesian population modeling and virtual bioequivalence assessment approach to establishing dissolution specifications for oral dosage forms. A generalizable semi-physiologically based pharmacokinetic absorption model with six gut segments and liver, connected to a two-compartment model of systemic disposition for bupropion hydrochloride oral dosage forms was developed. Prior information on model parameters for gut physiology, bupropion physicochemical properties, and drug product properties were obtained from the literature. The release of bupropion hydrochloride from immediate-, sustained- and extended-release oral dosage forms was described by a Weibull function. In vitro dissolution data were used to assign priors to the in vivo release properties of the three bupropion formulations. We applied global sensitivity analysis to identify the influential parameters for plasma bupropion concentrations and calibrated them. To quantify inter- and intra-individual variability, plasma concentration profiles in healthy volunteers that received the three dosage forms, each at two doses, were used. The calibrated model was in good agreement with both in vitro dissolution and in vivo exposure data. Markov Chain Monte Carlo samples from the joint posterior parameter distribution were used to simulate virtual crossover clinical trials for each formulation with distinct drug dissolution profiles. For each trial, an allowable range of dissolution parameters ("safe space") in which bioequivalence can be anticipated was established. These findings can be used to assure consistent product performance throughout the drug product life-cycle and to support manufacturing changes. Our framework provides a comprehensive approach to support decision-making in drug product development.

Pregnancy Has No Clinically Significant Effect on the Pharmacokinetics of Bupropion or Its Metabolites.

Bupropion (BUP) is a chiral antidepressant and smoking cessation aide with benefits and side effects correlated with parent and active metabolite concentrations. BUP is metabolized by CYP2B6, CYP2C19, and CYP3A4 to hydroxy-BUP (OH-BUP) as well as by 11β-hydroxysteroid dehydrogenase-1 and aldo-keto reductases to threohydrobupropion (Threo) and erythrohydrobupropion (Erythro), respectively. As pregnancy alters the activity of drug-metabolizing enzymes, the authors hypothesized that BUP metabolism and BUP metabolite concentrations would be altered during pregnancy, potentially affecting the efficacy and safety of BUP in pregnant women. Pregnant women (n = 8) taking BUP chronically were enrolled, and steady-state plasma samples and dosing interval urine samples were collected during pregnancy and postpartum. Maternal and umbilical cord venous blood samples were collected at delivery from 3 subjects, and cord blood/maternal plasma concentration ratios were calculated. The concentrations of BUP stereoisomers and their metabolites were measured. Paired t tests were used to compare pharmacokinetic parameters during pregnancy and postpartum. No significant changes were observed in the steady-state plasma concentrations, metabolite to parent ratios, formation clearances, or renal clearance of any of the compounds during pregnancy when compared with postpartum. The umbilical cord venous plasma concentrations of BUP and its metabolites were 30%-60% lower than maternal plasma concentrations. This study showed that there are no clinically meaningful differences in the stereoselective disposition of BUP or its metabolites during pregnancy, indicating that dose adjustment during pregnancy may not be necessary. The results also showed that the placenta provides a partial barrier for bupropion and its metabolite distribution to the fetus, with possible placental efflux transport of bupropion and its metabolites.

Treatment of Bupropion Toxicity with Lipid Emulsion

We have read with interest the case report, “Successful Management of Adolescent Bupropion Overdose with Intravenous Lipid Emulsion Therapy,” recently published in the Journal of Pediatric Intensive Care.[1] Lipid emulsion is effective in the treatment of acute toxicity induced by local anesthetics or nonlocal anesthetic drugs, including amitriptyline, bupropion, and verapamil, in pediatric patients.[2] A previous in vitro study reported that the magnitude of the reduction of the serum concentration of bupropion, which is a highly lipid-soluble antidepressant (log [octanol/water partition coefficient]: 3.2), was 46 by 2% lipid emulsion (Intralipid).[3] In addition, the magnitude of the sequestration of drugs with varied lipid solubility by lipid emulsion is dependent mainly on the lipid partition coefficient and partially on the volume of distribution, which appears to account for 88% of variations in the reduction of drug serum concentration by lipid emulsion.[3] As suggested by Bornstein et al, the lipid sink theory, which is considered the mechanism underlying the effect of lipid emulsion as a nonspecific antidote, states that lipid emulsion absorbs highly lipid-soluble drugs, such as bupivacaine (log [octanol/water partition coefficient]: 3.41), from the heart.[1] [4] However, the following comments should be considered to understand this case report well. First, the first administration of lipid emulsion improved the mental status of the patient.[1] On day 3, the second administration of lipid emulsion was performed due to the recurrence of an altered mental status.[1] The elimination half-life of bupropion is 29 ± 9 hours.[5] In addition, the absorption of a toxic dose following oral administration (enteral route) is more prolonged than that following intravenous administration, leading to extended toxicity.[6] In contrast, Intralipid has a very short half-life (13.7 ± 5.2 minutes).[7] Considering previous reports, the lipid phase of lipid emulsion appears to absorb highly lipid-soluble bupropion from the heart and brain for a very short period following lipid emulsion administration.[3] [7] Furthermore, 1% of plasma triglyceride concentration, which provides lipemic plasma without fat overload, is sufficient to exert scavenging and cardiotonic effects on the toxicity induced by an enteral overdose.[6] Thus, the altered mental status on day 3 following a marked improvement after the first administration of lipid emulsion may be ascribed to a greatly reduced concentration of Intralipid.[1] A previous report recommends the following lipid emulsion regimen to treat toxicity induced by enteral overdose: bolus administration of Intralipid 1.5 mL/kg for 1 minute and subsequently 0.25 mL/kg/min for an additional 3 minutes, followed by intravenous infusion of 0.025 mL/kg/min (up to 6.5 hours) to theoretically maintain a 1% plasma triglyceride concentration.[6] This regimen, as an adjuvant, can be used with supportive care in cases of toxicity induced by oral overdose.[6] However, further research in an in vivo model on the optimal dosing regimen of lipid emulsion for the treatment of toxicity following oral overdose of bupropion is needed because the pharmacokinetics of an oral overdose are different from those of intravenous overdose (e.g., local anesthetic systemic toxicity). Second, initially, lipid sink was widely accepted as the underlying mechanism of lipid emulsion treatment.[4] However, a previous study using a physiologically based pharmacokinetic model reported that lipid emulsion decreased only 11 and 18% bupivacaine concentrations in the heart and brain, respectively.[8] The free bupivacaine concentration was not significantly different between the control and lipid emulsion groups in an in vivo study after administration of a nontoxic dose of bupivacaine in humans.[9] Thus, lipid shuttle has recently been widely accepted as the mechanism of lipid emulsion treatment; it states that lipid emulsion absorbs lipid-soluble drugs, such as bupivacaine, from the heart and then the lipid emulsion, containing the sequestered lipid-soluble drug (e.g., bupivacaine), is transported to the liver and muscle for detoxification and storage, leading to enhanced redistribution.[4] We believe that this case report contributes valuable data on the efficacy of lipid emulsion treatment in bupropion toxicity and emphasizes the need for continuous infusion of lipid emulsion following the initial bolus administration in lipid emulsion treatment.

Bupropion Inhibits Serotonin Type 3AB Heteromeric Channels at Clinically Relevant Concentrations.

Bupropion, a Food and Drug Administration–approved antidepressant and smoking cessation aid, blocks dopamine and norepinephrine reuptake transporters and noncompetitively inhibits nicotinic acetylcholine and serotonin (5-HT) type 3A receptors (5-HT3ARs). 5-HT3 receptors are pentameric ligand-gated ion channels that regulate synaptic activity in the central and peripheral nervous system, presynaptically and postsynaptically. In the present study, we examined and compared the effect of bupropion and its active metabolite hydroxybupropion on mouse homomeric 5-HT3A and heteromeric 5-HT3AB receptors expressed in Xenopus laevis oocytes using two-electrode voltage clamp experiments. Coapplication of bupropion or hydroxybupropion with 5-HT dose dependently inhibited 5-HT–induced currents in heteromeric 5-HT type 3AB receptors (5-HT3ABRs) (IC50 = 840 and 526 μM, respectively). The corresponding IC50s for bupropion and hydroxybupropion for homomeric 5-HT3ARs were 10- and 5-fold lower, respectively (87 and 113 μM). The inhibition of 5-HT3ARs and 5-HT3ABRs was non–use dependent and voltage independent, suggesting bupropion is not an open channel blocker. The inhibition by bupropion was reversible and time-dependent. Of note, preincubation with a low concentration of bupropion that mimics therapeutic drug conditions inhibits 5-HT–induced currents in 5-HT3A and 5-HT3AB receptors considerably. In summary, we demonstrate that bupropion inhibits heteromeric 5-HT3ABRs as well as homomeric 5-HT3ARs. This inhibition occurs at clinically relevant concentrations and may contribute to bupropion’s clinical effects.SIGNIFICANCE STATEMENTClinical studies indicate that antagonizing serotonin (5-HT) type 3AB (5-HT3AB) receptors in brain areas involved in mood regulation is successful in treating mood and anxiety disorders. Previously, bupropion was shown to be an antagonist at homopentameric 5-HT type 3A receptors. The present work provides novel insights into the pharmacological effects that bupropion exerts on heteromeric 5-HT3AB receptors, in particular when constantly present at low, clinically attainable concentrations. The results advance the knowledge on the clinical effects of bupropion as an antidepressant.

Exposure to dilute concentrations of bupropion affects zebrafish early life stages

Psychiatric pharmaceuticals are one of the most prescribed active substances globally. Bupropion (BPP) is an antidepressant that acts via inhibition of norepinephrine and dopamine reuptake. It has been found in various water matrices, and thus its effects on aquatic organisms must be studied. The present study aimed to evaluate the acute toxic effects of BPP on zebrafish (Danio rerio) early life stages. For developmental analysis, organisms were exposed for 168 h to concentrations ranging from 0 to 82000 μg/L. Two other experiments were performed by exposing embryos to a wide range of concentrations (from 0 to 50000 μg/L) in order to evaluate BPP effects on embryonic behavior, using the Zebrabox and testing at the biochemical level (acetylcholinesterase, glutathione-S-transferase, lactate dehydrogenase and catalase). Developmental analysis indicated that BPP had low acute toxicity with a calculated 168 h-LC50 of 50346 μg/L. Concentrations equal to or above 44800 μg/L elicited several effects such as hatching delay, edemas and tail deformities. However, concentrations from 7300 μg/L upwards elicited equilibrium alteration. Behavioral analysis showed that BPP affected zebrafish locomotor behavior by decreasing activity at 0.6 μg/L, increasing activity at 8.8 and 158 μg/L, and decreasing activity at 50000 μg/L. Biochemical analysis showed an increase of AChE activity at 158 and 2812 μg/L, an increase in GST at the highest concentrations, CAT alteration and increase of LDH at 0.6, 2812 and 50000 μg/L. We can conclude that BPP affects zebrafish early life stages at environmental concentrations.

Degradation of Bupropion: Implications for Interpretation of Postmortem Case Data.

The interpretation of postmortem bupropion is often a challenge to the forensic toxicology community because of the instability of the parent compound. At the North Carolina Office of the Chief Medical Examiner (NC OCME) toxicology laboratory, one of the active metabolites, threobupropion, is used as a complementary indicator for the extent of exposure to the parent compound. Metabolite data will address postmortem normal concentrations as well as when bupropion was attributed to the cause of death. For 55 natural cases where bupropion was unattributed to the cause of death, the blood and liver mean threobupropion concentrations were 1.8 mg/L and 12.1 mg/kg, respectively, with median concentrations of 1.5 mg/L and 10 mg/kg, respectively. For the 51 suicidal ingestion cases when bupropion was attributed to the cause of death, the blood and liver mean threobupropion concentrations were 15.8 mg/L and 131.5 mg/kg, respectively, with median concentrations of 13.5 mg/L and 110 mg/kg, respectively. The laboratory completed a stability study over the course of 50 days to evaluate how bupropion and threobupropion degrade in postmortem blood, liver and liver homogenate. The samples were subjected to forensically relevant conditions by storing them at room temperature (RT, 20°C), refrigerated (4°C) and frozen (-20°C). While the concentration of bupropion decreased in all specimens, the rate of degradation of the RT samples was the most dramatic. The threobupropion metabolite appeared to be relatively stable. The postmortem case data along with the evaluation of potential degradation products should provide an overall picture to assist the toxicological community with the interpretation of bupropion found in routine casework.

Modified High Performance Liquid Chromatography Analysis for Bupropion and Naltrexone in Bulk and Tablets by using Green Mobilephase

A accurate, precise, specific modified High Performance Liquid Chromatography method was developed for the simultaneous quantification of Bupropion and Naltrexone in bulk and dosage forms. A C18 column (250 x 4.6mm; 5 µm Phenomenex) with green mobile phase containing 0.05% v/v N,N-Diisopropylethylamine (DIPEA) (pH6.5): water (25:75% v/v) 20°C was used and isocratic pump is used for elution and eluents were monitored at 251 and 281 nm. The retention times of bupropion and naltrexone were 2.692 min and at 4.56 min respectively and showed a good linearity in the concentration range from 1?g/mL to 200 ?g/mL of Bupropion and Naltroxone were prepared and detected by HPLC. Concentrations of Bupropion and Naltroxone 251 nm were found to be linear in the range of 5?g/mL-40?g/mL and 10?g/mL-90?g/mL respectively with a correlation coefficient of 0.98and 0.998 respectively. The average percent recoveries were found to be 99% for bupropion and naltrexone. The developed method fallows all the validation parameters like accuracy, precision, linearity, limit of detection, limit of quantitation and solution stability. Conclusion: The proposed method was validated as per International Conference on Harmonization guidelines and successfully applied to the simultaneous estimation of Bupropion and Naltrexone in bulk and dosage forms.

Influence of the selective antagonist of the NR2B subunit of the NMDA receptor, traxoprodil, on the antidepressant-like activity of desipramine, paroxetine, milnacipran, and bupropion in mice

Pre-clinical and clinical studies indicated that a blockade of the NMDA receptor complex creates new opportunities for the treatment of affective disorders, including depression. The aim of the present study was to assess the influence of traxoprodil (10 mg/kg) on the activity of desipramine (10 mg/kg), paroxetine (0.5 mg/kg), milnacipran (1.25 mg/kg), and bupropion (10 mg/kg), each at sub-therapeutic doses. Moreover, brain levels of traxoprodil and tested agents were determined using HPLC. The obtained results were used to ascertain the nature of occurring interaction between traxoprodil and studied antidepressants. The experiment was carried out on naïve adult male Albino Swiss mice. Traxoprodil and other tested drugs were administered intraperitoneally. The influence of traxoprodil on the activity of selected antidepressants was evaluated in forced swim test (FST). Locomotor activity was estimated to exclude false positive/negative data. To assess the influence of traxoprodil on the concentration of used antidepressants, their levels were determined in murine brains using HPLC. Results indicated that traxoprodil potentiated activity of all antidepressants examined in FST and the observed effects were not due to the increase in locomotor activity. Only in the case of co-administration of traxoprodil and bupropion, increased bupropion concentrations in brain tissue were observed. All tested agents increased the traxoprodil levels in the brain. Administration of a sub-active dose of traxoprodil with antidepressants from different chemical groups, which act via enhancing monoaminergic transduction, caused the antidepressant-like effect in FST in mice. The interactions of traxoprodil with desipramine, paroxetine, milnacipran, and bupropion occur, at least partially, in the pharmacokinetic phase.

Pharmacokinetics of Bupropion and Its Pharmacologically Active Metabolites in Pregnancy

Bupropion sustained release is used to promote smoking cessation in males and nonpregnant females. However, its efficacy as a smoking cessation aid during pregnancy is not reported. The pregnancy-associated changes in maternal physiology may alter the pharmacokinetics and pharmacodynamics of bupropion and consequently its efficacy in pregnant smokers. Therefore, the aims of this study were to determine the steady-state pharmacokinetics of bupropion during pregnancy and the effect of functional genetic variants of CYP2B6 and CYP2C19 on bupropion pharmacokinetics in pregnant women. Plasma and urine concentrations of bupropion and its metabolites hydroxybupropion (OHBUP), threohydrobupropion, and erythrohydrobupropion were determined by liquid chromatography-mass spectrometry. Subjects were genotyped for five nonsynonymous single-nucleotide polymorphisms that result in seven CYP2B6 alleles, namely *2, *3, *4, *5, *6, *7, and *9, and for CYP2C19 variants *2, *3, and *17 The present study reports that the isoform-specific effect of pregnancy on bupropion-metabolizing enzymes along with the increase of renal elimination of the drug could collectively result in a slight decrease in exposure to bupropion in pregnancy. In contrast, pregnancy-induced increase in CYP2B6-catalyzed bupropion hydroxylation did not impact the plasma levels of OHBUP, probably due to a higher rate of OHBUP glucuronidation, and renal elimination associated with pregnancy. Therefore, exposure to OHBUP, a pharmacologically active metabolite of the bupropion, appears to be similar to that of the nonpregnant state. The predicted metabolic phenotypes of CYP2B6*6 and variant alleles of CYP2C19 in pregnancy are similar to those in the nonpregnant state.

The relationship between bupropion and suicide in post-mortem investigations

We reviewed the 33727 postmortem toxicology investigations performed in Finland over a period of 5years (2009–2013) and identified those in which the antidepressant bupropion was detected. Cases positive for other antidepressant drugs were reviewed for comparison.The postmortem toxicological examination included, in all cases, the routine screening and quantification of hundreds of drugs and poisons using quality-controlled methods.Bupropion was detected in 65 cases. A large proportion of the bupropion-positive deaths resulted from suicide (55%). In fatal poisoning cases found positive for bupropion, the proportion of suicide was even higher (77%). The measured median bupropion postmortem blood concentration (0.69mg/L) was markedly higher than the normal therapeutic range in plasma in the treatment of depression (up to 0.1mg/L) and even higher in fatal bupropion poisonings (13mg/L).Only 14% of the deceased positive for bupropion were estimated to be drug abusers. However, nearly all of the drug abuse cases were from the last year of the study (2013), indicating a recent increase of the use of bupropion among drug abusers and possibly even abuse of bupropion itself.Suicide victims positive for bupropion were younger than those who died with other antidepressant drugs in their blood. In addition, the percentage of fatal poisonings among bupropion-positive postmortem cases was higher than among the users of other antidepressant drugs. Suicide was significantly more common among the deceased positive for bupropion than among users of other antidepressant drugs.An unknown degree of bupropion degradation before the assay and post-mortem redistribution of bupropion may have impacted the measured levels. Nonetheless, all post-mortem concentrations of bupropion were elevated and especially high concentrations were detected in suicides.

Bupropion therapy during pregnancy: the drug and its major metabolites in umbilical cord plasma and amniotic fluid

Bupropion is used for treatment of depression during pregnancy. However, its use as a smoking cessation aid for pregnant women is currently under evaluation. The aim of this opportunistic study was to investigate the transfer of bupropion and its major pharmacologically active metabolites, hydroxybupropion and threohydrobupropion, across the placenta invivo. Inaddition, the concentrations of the drug and its metabolites were determined in the amniotic fluid. The following samples were collected at deliveries from 22 women taking bupropion: maternal blood (n= 22), umbilical cord venous blood (n= 22), and amniotic fluid (n= 9). The concentrations of the drug and its metabolites in blood plasma and amniotic fluid were determined by means of liquid chromatography-mass spectrometry. Placental passage was calculated as a ratio of umbilical cord venous plasma to maternal plasma concentrations. The levels of hydroxybupropion and threohydrobupropion inumbilical cord venous plasma were invariably lower than their corresponding concentrations in maternal plasma. The concentrations of bupropion in umbilical cord plasma were lower than in maternal plasma in the majority of the maternal-cord blood pairs. The median values of the umbilical cord venous plasma to maternal plasma ratios were: bupropion, 0.53 (interquartile range 0.35, n= 18), hydroxybupropion, 0.21 (interquartile range 0.12, n= 18), and threohydrobupropion, 0.61 (interquartile range 0.11, n= 21). In umbilical cord venous plasma, the median concentration of bupropion was 5.3 ng/mL; hydroxybupropion, 103.6 ng/mL; and threohydrobupropion, 59.6 ng/mL. Bupropion and its metabolites were detectable in the amniotic fluid but the concentrations ofthreohydrobupropion were higher than those in the corresponding umbilical cord venous plasma. Bupropion and its active metabolites cross the placenta to the fetal circulation. The concentrations of hydroxybupropion and threohydrobupropion in umbilical cord venous plasma were higher than bupropion concentrations suggesting a higher fetal exposure to the metabolites than the parent drug. The higher levels of threohydrobupropion in the amniotic fluid than those in umbilical cordvenous plasma suggest that enzymes involved in the metabolism of bupropion to threohydrobupropion are most likely active in the fetus.The biological consequences of fetal exposure to maternally administered bupropion and/or its active metabolites via placental transferand recirculation of the amniotic fluid are yet to be determined.

Identification of Novel Drug Targets in T-Cell Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer and one of the leading causes of death in children with tumors. Genetic changes in T-cell acute lymphoblastic leukemia (T-ALL) are relatively well known, but the underlying molecular processes driving the disease remain insufficiently understood. Better knowledge of molecular events in T-ALL would improve our understanding of the development and maintenance of the disease and could also lead to the development of targeted and more effective treatments.We have compiled a large gene expression data-set from microarray studies of various hematological and lymphoid malignancies and healthy tissues that use a uniform technical platform (Affymetrix HG U133 Plus 2.0) (see abstract by Liuksiala et al). Data-set includes 1302 healthy samples and 4418 leukemia samples: 1713 acute myeloid leukemias, 1648 precursor B-ALLs, 801 chronic lymphocytic leukemias, 385 T-ALLs, and 215 chronic myeloid leukemias. From this data-set, we identified a number of transcription factors (TFs) that were differentially expressed in T-ALL, including high expression of NOTCH1 and BCL11B as previously reported (Weng et al Science 2004; Gutierrez et al Blood 2011). Several novel candidate TFs with specific expression in T-ALLs were also discovered, including strong expression of two poorly characterized TFs, SIX6 and PCBP3. These findings were validated using real-time quantitative PCR (RT-qPCR) in a cell line panel consisting of T-ALL and pre-B-ALL cell lines as well as healthy controls.We next sought to identify novel drug targets in T-ALL by comparing our leukemia expression data-set with the therapeutic target database (TTD). TTD is a database providing information about the known and explored therapeutic protein and nucleic acid targets, and the corresponding drugs aimed at these targets. We identified high expression of a nicotinic acetylcholine receptor (nAChR) subunit CHRNA3 (cholinergic receptor, nicotinic, alpha 3), which is a target of nAChR inhibitor bupropion. RT-qPCR confirmed the high expression of CHRNA3 in T-ALL cell lines but not in pre-B-ALL cells or healthy controls. The effect of bupropion was tested in Jurkat cells which represent T-ALL cell line with high expression of CHRNA3. Increasing concentrations of bupropion (1-100µM) resulted in dose-dependent decrease in proliferation of Jurkat cells as measured by cell viability assay AlamarBlue. As a control, cell lines with low level of CHRNA3 expression (CCRF-CEM and REH) were treated as well but these cells did not show any changes in the rate of proliferation.In summary, we have identified several candidate transcription factors which could have a leukemic role in T-ALL. Furthermore, we identified high expression of CHRNA3 in T-ALL, suggesting a role for the cholinergic system in T-cell leukemia, and thus a novel avenue in search of putative therapeutic options. DisclosuresNo relevant conflicts of interest to declare.

Effect of CYP2B6*6 on Steady-State Serum Concentrations of Bupropion and Hydroxybupropion in Psychiatric Patients

The clinical effect of bupropion is mediated by its active metabolite hydroxybupropion. Previous studies have reported conflicting impact of the CYP2B6*6 variant allele on the formation of hydroxybupropion from bupropion. The aim of this study was to clarify the effect of CYP2B6*6 and secondarily CYP2D6 genotype on steady-state serum concentrations of bupropion and hydroxybupropion in a large population of psychiatric patients. Retrospective information about dose-adjusted serum concentrations (C/D ratios) of bupropion and hydroxybupropion, CYP2B6 genotype (ie, data on the 2B6*6 polymorphisms 516G>T and 785A>G) and CYP2D6 genotype, was obtained from a therapeutic drug monitoring database (n = 132 patients). C/D ratios of bupropion and hydroxybupropion, and metabolic ratios, were compared between CYP2B6 genotype subgroups by multivariate mixed-model analyses (2B6*1/*1 was defined as control group). In the analyses, CYP2D6 genotype was also included as a covariate. Homozygous 2B6*6 carriers (n = 7) had significantly lower C/D ratios of hydroxybupropion compared with controls (n = 79), that is, estimated mean 5.8 versus 13.0 nmol·L·mg (P < 0.001). C/D ratio of hydroxybupropion in heterozygous *6 carriers (12.1 nmol·L·mg; n = 46) did not significantly differ compared with controls (P = 0.32). The hydroxybupropion/bupropion metabolic ratios in heterozygous and homozygous 2B6*6 carriers were significantly lower than in controls (P = 0.001 and P < 0.001, respectively). CYP2D6 genotype did not significantly alter the hydroxybupropion C/D ratio, but higher bupropion values were observed in poor versus extensive CYP2D6 metabolizers (P = 0.020). This study shows that the CYP2B6*6 variant allele is associated with significantly reduced formation of the active bupropion metabolite in psychiatric patients. Our findings suggest that dose-adjusted serum concentrations of hydroxybupropion at steady state is approximately halved in homozygous CYP2B6*6 carriers, which might imply risk of reduced clinical response in this patient subgroup. The CYP2D6 genotype does not affect hydroxybupropion concentrations and is therefore unlikely to impact bupropion treatment.

Interactions between bupropion and 3,4-methylenedioxymethamphetamine in healthy subjects.

3,4-Methylenedioxymethamphetamine (MDMA; "ecstasy") is a popular recreational drug. The aim of the present study was to explore the role of dopamine in the psychotropic effects of MDMA using bupropion to inhibit the dopamine and norepinephrine transporters through which MDMA releases dopamine and norepinephrine by investigating. The pharmacodynamic and pharmacokinetic interactions between bupropion and MDMA in 16 healthy subjects were investigated using a double-blind, placebo-controlled, crossover design. Bupropion reduced the MDMA-induced elevations in plasma norepinephrine concentrations and the heart rate response to MDMA. In contrast, bupropion increased plasma MDMA concentrations and prolonged its subjective effects. Conversely, MDMA increased plasma bupropion concentrations. These results indicate a role for the transporter-mediated release of norepinephrine in the cardiostimulant effects of MDMA but do not support a modulatory role for dopamine in the mood effects of MDMA. These results also indicate that the use of MDMA during therapy with bupropion may result in higher plasma concentrations of both MDMA and bupropion and enhanced mood effects but also result in lower cardiac stimulation.

Interaction of Bupropion with 5-HT3A Receptors

For more than two decades, bupropion has been clinically prescribed for the treatment of depression (Wellbutrin®), and more recently for smoking cessation (Zyban®). Bupropion is conventionally described as a dual norepinephrine dopamine reuptake inhibitor, therefore effective as an antidepressant. However, we and others have shown that it also interacts with receptors of the Cys-loop superfamily, namely neuronal nicotinic acetylcholine receptors. In the continuum of exploring the molecular interactions of bupropion with other prominent members of the Cys-loop superfamily, we report here that bupropion additionally inhibits 5-hydroxytryptamine (serotonin) type 3A receptors (5-HT3ARs).5-HT3ARs are cation-conducting, homo-pentameric ligand-gated ion channels of the Cys-loop superfamily which are structurally and functionally distinct from other serotonin receptors that are G-proteins. 5-HT3 receptors are current targets for anti-emetics mainly used in cancer chemotherapy, as well as potential future targets for disorders including anxiety, schizophrenia, and Alzheimer's disease.Here we characterized our newly-identified interaction of bupropion with 5-HT3ARs with electrophysiological and radioligand binding studies. In oocytes, bupropion inhibited 5-HT3AR-mediated currents with an IC50 value of 87 µM (nH = 1.2). That 300 µM bupropion inhibited [3H]-5-HT or [3H]-granisetron (a competitive antagonist) binding by ∼ 20% indicated at best weak interaction with the agonist binding site. In contrast, the effect of different concentrations of bupropion on serotonin concentration-response curves suggested a non-competitive nature of interaction. Along these lines, importantly, the inhibition of serotonin-evoked currents recorded from oocytes was proportional to the length of preincubation time with bupropion.In summary, our results are indicative of a negative allosteric interaction of bupropion with the 5-HT3AR. Currently, experiments are underway to identify the site(s) of interaction for bupropion within the 5- HT3AR.

Metabolism and disposition of bupropion in pregnant baboons (Papio cynocephalus).

Recent in vitro data obtained in our laboratory revealed similarities between baboons and humans in the biotransformation of bupropion (BUP) by both hepatic and placental microsomes. These data supported the use of baboons to study BUP biotransformation during pregnancy. The aim of this investigation was to determine the pharmacokinetics of BUP in baboons during pregnancy and postpartum, as well as fetal exposure to the drug after intravenous administration. Pregnant baboons (n = 5) received a single intravenous bolus dose of bupropion hydrochloride (1 mg/kg) at gestational ages 94-108 days (midpregnancy), 142-156 days (late pregnancy), and 6 weeks postpartum. Blood and urine samples were collected for 12 and 24 hours, respectively. The concentrations of BUP, hydroxybupropion (OH-BUP), threohydrobupropion, and erythrohydrobupropion in plasma were determined by liquid chromatography-tandem mass spectrometry. Relative to the postpartum period, the average midpregnancy clearance of BUP trended higher (3.6 ± 0.15 versus 2.7 ± 0.28 l/h per kg) and the average C(max) (294 ± 91 versus 361 ± 64 ng/ml) and the area under the curve (AUC) of BUP values (288 ± 22 versus 382 ± 42 h·ng/ml) trended lower. AUC(OH-BUP) also tended to be lower midpregnancy compared with postpartum (194 ± 76 versus 353 ± 165 h·ng/ml). Whereas the observed trend toward increased clearance of BUP during baboon pregnancy could be associated with a pregnancy-induced increase in its biotransformation, the trend toward increased renal elimination of OH-BUP may overshadow any corresponding change in the hydroxylation activity of CYP2B.

Bupropion and Escitalopram During Lactation

To report a case of seizure-like symptoms in an infant exposed to bupropion and escitalopram through breastfeeding. A 6.5-month-old female infant, breastfed by a mother treated with bupropion XL 150 mg/d and escitalopram 10 mg/d for depression, presented to our hospital with severe emesis and tonic seizure-like symptoms. The symptoms resolved with supportive therapy. Urine toxicology screen in the infant revealed bupropion and escitalopram. Bupropion, and its active metabolite, hydroxybupropion, were analyzed and quantified both in the infant's serum and in the breast milk. Diagnostic workup for seizure etiologies was otherwise negative. After being asymptomatic for 48 hours, her discharge diagnosis was adverse events associated with bupropion and escitalopram in lactation. An objective causality assessment (Naranjo assessment) revealed that this adverse effect was probable. The adverse events in our case were associated with serum concentrations of bupropion and hydroxybupropion that are lower than the reported therapeutic range, perhaps suggesting that infants, compared with adults, may have a higher susceptibility to the epileptogenic effects of bupropion and/or hydroxybupropion. Furthermore, although we do not have escitalopram serum concentrations, this drug interaction may have had a contributing role in this case, possibly because of cytochrome P4502D6 inhibition by bupropion and metabolites. As the number of reproductive-aged women requiring polytherapy to control their depression is increasing, further research is needed to establish the safety of combined antidepressants, such as selective serotonin reuptake inhibitors and bupropion, during lactation.

Mechanism of an unusual, but clinically significant, digoxin–bupropion drug interaction

An unusual, but clinically significant, digoxin (DIG)-bupropion (BUP) drug interaction (DDI), in which BUP increased DIG renal clearance by 80% is reported. To investigate the mechanism(s) of this unusual DDI, first the effect of BUP, its circulating metabolites or their combination on [(3) H]-DIG transport by cells expressing human P-gp or human OATP4C1 was determined. Second, the study asked whether this DDI could be replicated in the rat so that it could be used to conduct mechanistic studies. Then, the effect of BUP and its rat metabolites on [(3) H]-DIG transport were tested by cells expressing rat Oatp4c1. Bupropion and its metabolites had no effect on human P-gp mediated transepithelial transport of [(3) H]-DIG. Bupropion and hydroxybupropion (HBUP) significantly stimulated H-OATP4C1 mediated transport of [(3) H]-DIG. In addition, BUP cocktail (BUP plus its metabolites) significantly increased the H-OATP4C1 mediated transport of [(3) H]-DIG, and partially reversed the inhibition by 100 µm DIG. However, erythro-hydrobupropion (EBUP) and threo-hydrobupropion (TBUP) did not affect the [(3) H]-DIG uptake by H-OATP4C1 cells. Bupropion administration significantly increased digoxin renal clearance in rats. Surprisingly, bupropion significantly inhibited r-Oatp4c1 mediated transport of [(3) H]-DIG at clinically relevant unbound plasma concentrations of BUP or those observed in the rat study, while HBUP or TBUP did not. These data support our hypothesis that at clinically relevant plasma concentrations, bupropion and its metabolites activate H-OATP4C1 mediated DIG tubular secretion, and could possibly explain the increase in digoxin renal clearance produced by bupropion. While bupropion increased digoxin renal clearance in the rat, it appeared to do so by inhibiting r-Oatp4c1-mediated digoxin renal reabsorption.