Simultaneous quantitative determination of bupropion and its three major metabolites in human umbilical cord plasma and placental tissue using high-performance liquid chromatography-tandem mass spectrometry

Bupropion Mediated Effects on Depression, Attention Deficit Hyperactivity Disorder, and Smoking Cessation

Bupropion had been in use since the late 1980s as an unconventional treatment for depression. Unlike other antidepressants, bupropion has no serotonergic activity and inhibits the reuptake of norepinephrine and dopamine. The drug has been used to treat depression, Attention Deficit Hyperactivity Disorder (ADHD), and smoking cessation. This investigation reviews the pharmacokinetic and pharmacodynamic effects of bupropion and its mechanisms of action and interactions with other drugs. We evaluated the efficacy of major on and off-label uses of bupropion, focusing on the indications, benefits, and adverse effects. Our review demonstrates that bupropion is superior to placebo and non-inferior to SSRIs such as escitalopram in treating major depressive disorder. More research is needed to determine positive patient-centered outcomes such as increases in quality of life. In the case of ADHD, the evidence for efficacy is mixed with poorly conducted randomized clinical trials, small sample sizes, and a lack of long-term assessments. The same is true in the case of bipolar disorder in which there is still limited and controversial data available on bupropion's safety and efficacy. In the case of smoking cessation, bupropion is found to be an effective anti-smoking drug with synergistic benefits when used as a combination therapy. We conclude that bupropion has the potential to provide benefit for a subset of patients who do not tolerate other typical antidepressants or anti-smoking therapies or for those whose treatment goals align with bupropion's unique side effect profile, such as smokers who wish to quit and lose weight. Additional research is needed to determine the drug's full clinical potential, particularly in the areas of adolescent depression and combination therapy with varenicline or dextromethorphan. Clinicians should use this review to understand the varied uses of the drug and identify the situations and patient populations in which bupropion can lend its greatest benefit.

Spectrofluorimetric method for determination of bupropion in pharmaceutical dosage forms

OBJECTIVE

Bupropion is a noradrenaline and dopamine reuptake inhibitor which is used as an antidepressant drug. Few HPLC and spectrophotometric methods have been reported before for the determination of bupropion. Most of the previous methods reported for determination of bupropion in pharmaceutical dosage forms are somehow dangerous to health and environment because of using organic solvents.

METHOD

In the present method bupropion was determined in pharmaceutical dosage forms by spectrofluorimetry after ion-pair complex formation with eosin Y. The ion-pair complex formation was optimized for reagent amount, buffer pH and time.

RESULT

The developed method was linear over the range of 3-120μgmL^-1 with an acceptable precision (CV<1.5%) and accuracy (Error<1%).

CONCLUSION

The present method is applicable for determination of bupropion in pharmaceutical dosage forms for routine quality control analysis.

Application of wavelet and Fuorier transforms as powerful alternatives for derivative spectrophotometry in analysis of binary mixtures: A comparative study

Two signal processing methods, namely, Continuous Wavelet Transform (CWT) and the second was Discrete Fourier Transform (DFT) were introduced as alternatives to the classical Derivative Spectrophotometry (DS) in analysis of binary mixtures. To show the advantages of these methods, a comparative study was performed on a binary mixture of Naltrexone (NTX) and Bupropion (BUP). The methods were compared by analyzing laboratory prepared mixtures of the two drugs. By comparing performance of the three methods, it was proved that CWT and DFT methods are more efficient and advantageous in analysis of mixtures with overlapped spectra than DS. The three signal processing methods were adopted for the quantification of NTX and BUP in pure and tablet forms. The adopted methods were validated according to the ICH guideline where accuracy, precision and specificity were found to be within appropriate limits.

Simultaneous determination of naltrexone and bupropion in their co-formulated tablet utilizing green chromatographic approach with application to human urine

A rapid, simple and accurate micellar HPLC-method was adopted and validated for concurrent quantification of naltrexone hydrochloride (NTX) and bupropion hydrochloride (BUP). The proposed method was conducted on RP-18 LiChrosorb® column (150 mm × 4.6 mm i.d. 5-µm particle size) at 25 °C, as a stationary phase and a mixture of 0.175 M sodium dodecyl sulphate (SDS), 0.3% triethanolamine (TEA) and 12% n-propanol in 0.02 M ortho (o)-phosphoric acid of pH 3.5 as a developing system. It was pumped at a flow rate of 1.2 mL/min, with ultraviolet detection at 210 nm. The linearity ranges were 0.5–15.0 µg/mL and 1.2–18.0 µg/mL, with detection limits of 0.10 and 0.31 µg/mL and quantification limits of 0.30 and 0.93 µg/mL for NTX and BUP, respectively. The studied drugs were successfully quantified by applying the proposed method in their co-formulated tablet. The cited method was also applied for in-vitro quantification of BUP in spiked human urine without prior extraction.

Toxic compounds from tobacco in placenta samples analyzed by UPLC-QTOF-MS

Polycyclic aromatic hydrocarbons (PAHs), tobacco-specific nitrosamines (TSNAs) and aromatic amines are carcinogens present in cigarette smoke. These compounds are distributed in the human body and they could be transferred to the foetus during the pregnancy. Placenta is the main barrier to these toxic compounds and its study is the objective of this work. A method based on solid-phase extraction (SPE) with ultra-performance liquid chromatography-tandem quadrupole-time-of-flight mass spectrometry (UPLC-QTOF-MS) has been examined and optimized for the analysis of 9 target analytes (4 tobacco-specific nitrosamines and some of their metabolites, 3 aromatic amines, nicotine and cotinine) in 26 placenta samples from smoking and non-smoking women. Limits of detection (LODs) were in the range of 3-27ng/g of placenta. Nicotine, cotinine, N-nitrosoanatabine (NAT) and 4-(methylnitrosamino)-1- (3-pyridyl)-1-butanone (NNK) metabolite, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) were detected in the placenta samples of smoking woman. Nicotine was detected in 3 out of 8 placentas from smoking women, always below the limit of quantification (88ng/g). This could be expected, as the half-life of nicotine in the body is limited to about 0.5-3h. Cotinine, the main metabolite from nicotine, was detected in all placentas from smoking women at concentrations between 17.2 and 61.8ng/g, reaching the highest values for those women that smoked the highest number of cigarettes. NAT and NNAL were detected in all placentas from smoking women, always below the limit of quantification (40ng/g and 33ng/g respectively).

Postnatal Cardiovascular Consequences in the Offspring of Pregnant Rats Exposed to Smoking and Smoking Cessation Pharmacotherapies

Approximately 20% of pregnant women smoke despite intentions to quit. Smoking cessation drugs, such as nicotine replacement therapy (NRT) and bupropion, are recommended treatments. Adverse cardiovascular outcomes in offspring have raised concerns about NRT's safety during pregnancy. However, the effect of bupropion is unknown. Using a rat model, we determined whether NRT and bupropion interventions during pregnancy are safer than continued smoking on offspring's cardiovascular function. Male offspring of controls and dams exposed to cigarette smoke (1.6 packs/day, inhalation), nicotine (2 mg/kg/d subcutaneously), and bupropion (13 mg/kg twice daily orally) were assessed for fetoplacental weight, cardiac function, blood pressure, and vascular reactivity. Fetoplacental weights were decreased and spontaneous beating and intracellular calcium in neonatal cardiomyocytes were increased in smoking, nicotine, and bupropion offspring; however, these effects were more accentuated in smoking followed by nicotine and bupropion offspring. Increased heart rate and decreased cardiac output, stroke volume, and left ventricular percent posterior wall thickening were observed in smoking, nicotine, and bupropion offspring. The left ventricular mass was reduced in smoking and nicotine but not in bupropion offspring. Blood pressure was higher with decreased endothelium-dependent relaxation and exaggerated vascular contraction to angiotensin II in smoking and nicotine offspring, with more pronounced dysfunctions in smoking than nicotine offspring. Maternal bupropion did not impact offspring's blood pressure, endothelium-dependent relaxation, and vascular contraction. In conclusion, maternal nicotine intervention adversely affects offspring's cardiovascular outcomes, albeit less severely than continued smoking. However, bupropion causes cardiac derangement in offspring but does not adversely affect blood pressure and vascular function.

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

BACKGROUND

Bupropion is used for treatment of depression during pregnancy. However, its use as a smoking cessation aid for pregnant women is currently under evaluation.

OBJECTIVE

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 in vivo. In addition, the concentrations of the drug and its metabolites were determined in the amniotic fluid.

STUDY DESIGN

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.

RESULTS

The levels of hydroxybupropion and threohydrobupropion in umbilical 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 of threohydrobupropion were higher than those in the corresponding umbilical cord venous plasma.

CONCLUSION

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 cord venous 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 transfer and recirculation of the amniotic fluid are yet to be determined.

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.

Development and validation of a high-throughput stereoselective LC-MS/MS assay for bupropion, hydroxybupropion, erythrohydrobupropion, and threohydrobupropion in human plasma

A stereoselective analytical method was developed and validated for the quantification of bupropion, and principle metabolites hydroxybupropion, erythrohydrobupropion and threohydrobupropion in human plasma. Separation of individual enantiomers (R)-bupropion, (S)-bupropion, (R,R)-hydroxybupropion, (S,S-hydroxybupropion), (1S,2S)-threohydrobupropion, (1R,2R)-threohydrobupropion, (1R,2S)-erythrohydrobupropion, and (1S,2R)-erythrohydrobupropion was achieved utilizing an α1-acid glycoprotein column within a 12-min run time. Chromatograph separation was significantly influenced by mobile phase pH and variability between columns. Analytes were quantified by positive ion electrospray tandem mass spectrometry following plasma protein precipitation with 20% trichloroacetic acid. Identification of erythrohydrobupropion enantiomer peaks and threohydrobupropion enantiomer peaks was achieved by sodium borohydride reduction of enantiopure (R)- and (S)-bupropion. Initial assay validation and sensitivity determination was on AB Sciex 3200, 4000 QTRAP, and 6500 mass spectrometers. Accuracy and precision were within 15% for each analyte. The assay was fully validated over analyte-specific concentrations using an AB Sciex 3200 mass spectrometer. Intra- and inter-assay precision and accuracy were within 12% for each analyte. The limits of quantification for bupropion (R and S), hydroxybupropion (R,R and S,S), threohydrobupropion (1S,2S and 1R,2R), and erythrohydrobupropion (1R,2S and 1S,2R) were 0.5, 2, 1, and 1ng/mL, respectively. All analytes were stable following freeze thaw cycles at -80°C and while stored at 4°C in the instrument autosampler. This method was applicable to clinical pharmacokinetic investigations of bupropion in patients. This is the first chromatographic method to resolve erythrohydrobupropion and threohydrobupropion enantiomers, and the first stereoselective LC-MS/MS assay to quantify bupropion, and principle metabolites hydroxybupropion, erythrohydrobupropion, and threohydrobupropion in human plasma.

Metabolism of bupropion by carbonyl reductases in liver and intestine

Bupropion's metabolism and the formation of hydroxybupropion in the liver by cytochrome P450 2B6 (CYP2B6) has been extensively studied; however, the metabolism and formation of erythro/threohydrobupropion in the liver and intestine by carbonyl reductases (CR) has not been well characterized. The purpose of this investigation was to compare the relative contribution of the two metabolism pathways of bupropion (by CYP2B6 and CR) in the subcellular fractions of liver and intestine and to identify the CRs responsible for erythro/threohydrobupropion formation in the liver and the intestine. The results showed that the liver microsome generated the highest amount of hydroxybupropion (Vmax = 131 pmol/min per milligram, Km = 87 μM). In addition, liver microsome and S9 fractions formed similar levels of threohydrobupropion by CR (Vmax = 98-99 pmol/min per milligram and Km = 186-265 μM). Interestingly, the liver has similar capability to form hydroxybupropion (by CYP2B6) and threohydrobupropion (by CR). In contrast, none of the intestinal fractions generate hydroxybupropion, suggesting that the intestine does not have CYP2B6 available for metabolism of bupropion. However, intestinal S9 fraction formed threohydrobupropion to the extent of 25% of the amount of threohydrobupropion formed by liver S9 fraction. Enzyme inhibition and Western blots identified that 11β-dehydrogenase isozyme 1 in the liver microsome fraction is mainly responsible for the formation of threohydrobupropion, and in the intestine AKR7 may be responsible for the same metabolite formation. These quantitative comparisons of bupropion metabolism by CR in the liver and intestine may provide new insight into its efficacy and side effects with respect to these metabolites.

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.

Emerging drugs of abuse: current perspectives on substituted cathinones

Substituted cathinones are synthetic analogs of cathinone that can be considered as derivatives of phenethylamines with a beta-keto group on the side chain. They appeared in the recreational drug market in the mid-2000s and now represent a large class of new popular drugs of abuse. Initially considered as legal highs, their legal status is variable by country and is rapidly changing, with government institutions encouraging their control. Some cathinones (such as diethylpropion or pyrovalerone) have been used in a medical setting and bupropion is actually indicated for smoking cessation. Substituted cathinones are widely available from internet websites, retail shops, and street dealers. They can be sold under chemical, evocative or generic names, making their identification difficult. Fortunately, analytical methods have been developed in recent years to solve this problem. Available as powders, substituted cathinones are self-administered by snorting, oral injestion, or intravenous injection. They act as central nervous system stimulants by causing the release of catecholamines (dopamine, noradrenaline, and serotonin) and blocking their reuptake in the central and peripheral nervous system. They may also decrease dopamine and serotonin transporter function as nonselective substrates or potent blockers and may inhibit monoamine oxidase effects. Nevertheless, considerable differences have been found in the potencies of the different substituted cathinones in vitro. Desired effects reported by users include increased energy, empathy, and improved libido. Cardiovascular (tachycardia, hypertension) and psychiatric/neurological signs/symptoms (agitation, seizures, paranoia, and hallucinations) are the most common adverse effects reported. Severe toxicity signs compatible with excessive serotonin activity, such as hyperthermia, metabolic acidosis, and prolonged rhabdomyolysis, have also been observed. Reinforcing potential observed in animals predicts a high potential for addiction and abuse in users. In case of overdose, no specific antidote exists and no curative treatment has been approved by health authorities. Therefore, management of acute toxic effects is mainly extrapolated from experience with cocaine/amphetamines.