Carbamazepine-10,11-epoxide Research Articles

Impact of emerging pollutants mixtures on marine and brackish phytoplankton: diatom Phaeodactylum tricornutum and cyanobacterium Microcystis aeruginosa

Pharmaceuticals and ionic liquids (ILs) are emerging as significant micropollutants with environmental presence and potential ecological impacts. The possible simultaneous occurrence of these two groups of pollutants in aquatic environments raises complex challenges due to their diverse chemical properties and potential for interactive effects. Given the documented widespread presence of pharmaceuticals and the emerging concerns about ILs, the study aims to evaluate the adverse effects of binary mixtures of imidazolium ionic liquid IM1-8C(CN)3 and two representatives of pharmaceuticals: antibiotic oxytetracycline (OXTC) and metabolite carbamazepine 10,11 epoxide (CBZ-E) on the brackish cyanobacterium Microcystis aeruginosa and the marine diatom Phaeodactylum tricornutum during chronic exposure experiments. A comprehensive approach was employed, incorporating various endpoints including oxidative stress, chlorophyll a fluorescence, detailed photoprotective and photosynthetic pigment profiles of target microorganisms to assess modes of action and identify the mixture effects of the selected substances.The observed alterations in pigment production affecting carotenoids synthesis in both selected species may be attributed to the differential impacts of these substances on the photosynthetic pathways and metabolic processes in the cyanobacterial and diatom cells. Changes in chlorophyll a fluorescence-specific parameters suggest impairment of the photosynthetic activity, particularly affecting the efficiency of photosystem II.The application of Concentration Addition (CA) and Independent Action (IA) mathematical models, complemented by the evaluation of Model Deviation Ratios (MDR), revealed predominantly antagonistic interactions within the studied mixtures. The findings of this study provide important insights into the effects of mixtures of organic micropollutants and their potential impact on environment including brackish and marine waters.

A carbamazepine metabolite activates NLRP3 and controls skin homing of CD8+ T-cells in SJS/TEN

BackgroundStevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe adverse drug reactions with extensive keratinocyte death. Carbamazepine (CBZ), the most commonly implicated drug in SJS/TEN, is metabolized by the cytochrome P450 enzyme 3A4 (CYP3A4) into carbamazepine-10,11-epoxide (CBZE) in the liver. While CD8+ cytotoxic T cells play an important role in SJS/TEN, the underlying mechanism of exuberant immune response by CD8+ T cells in these conditions remains incompletely understood. ObjectivesTo examine the expression of NLRP3 inflammasome and their skin migration in CBZE-induced SJS/TEN. MethodsThe expression of the NLRP3 inflammasome complex in skin lesions, sera, and blister fluids of SJS/TEN patients were analyzed by immunohistochemistry and enzyme-linked immunosorbent assay. NLRP3 formation and CD8+ T cell activation status and their functions were examined by immunoblotting, immunofluorescence, and chemotaxis assays. ResultsThe expression of the NLRP3 inflammasome complex was greatly increased in skin lesions of SJS/TEN patients. Moreover, IL-1β and IL-18 levels in sera and blister fluids of SJS/TEN patients were approximately 3-fold higher than those in healthy individuals, with a linear correlation between IL-1β levels and disease activity. CBZE induced NLRP3 inflammasome formation, upregulated CXCL9/CXCL10 levels, and activated CD8+ cytotoxic T cell functions via IL-1β/IL-1R or IL-18/IL-18R signaling in SJS/TEN keratinocytes, which promoted CD8+ cytotoxic T cell migration in SJS/TEN patients. ConclusionThis study showed that CBZE promoted NLRP3 inflammasome formation and strengthened the activation and function of CD8+ cytotoxic T cells in the skin, which contributed to the initiation and progression of SJS/TEN.

Biotransformation of carbamazepine and nicotine in juvenile American alligator (Alligator mississippiensis) in vitro hepatic S9 vs. in situ perfused liver

American alligators (Alligator mississippiensis) are apex predators and sentinel species in the coastal wetland ecosystem along the Gulf of Mexico. There is concern for alligator exposure and susceptibility to chemical contaminants due to their high trophic level and lower metabolic capability. At present, their hepatic biotransformation capacity to metabolize or detoxify contaminants has not been comprehensively determined. In this study, the hepatic biotransformation capability of juvenile American alligators to metabolize two commonly found environmental pharmaceuticals: carbamazepine (CBZ) or nicotine (NCT) was evaluated. The formation of their respective primary metabolites, i.e., carbamazepine-10,11-epoxide (CBZ-E) and cotinine (CTN), was evaluated at 10 μM (within the human therapeutic range). The in vitro S9 and a novel in situ liver perfusion assays were used to characterize and compare metabolic ability in isolated hepatic enzymes vs. whole organ (liver). For CBZ, the perfused livers exhibited only 30% of intrinsic formation clearance (CLf,int) relative to the S9 assay. The metabolism of NCT was not detectable in the S9 assay and was only observed in the perfused liver assay. Compared to the corresponding rat models (S9 or perfused livers),alligators' CLf,int was 2060% for CBZ and 50% for NCT of rats. Additionally, NCT exposure increased lactate levels in perfused livers indicating metabolic stress. This study provides insight into the hepatic capability of alligators to metabolize CBZ and NCT using an established in vitro (S9) system and a newly developed in situ liver perfusion system.

Spectroscopic study of drug–drug interactions: influence of two over-the-counter drugs on the albumin binding affinities of carbamazepine and its major metabolite

BackgroundMultidrug regimens can increase the risk of drug–drug interactions at the level of albumin binding especially for drugs with narrow therapeutic windows such as carbamazepine (CBZ). This risk is particularly heightened for CBZ which is mainly metabolized to the active carbamazepine-10,11-epoxide (CBZE) that has been identified as contributory to both the therapeutic efficacy and severity of toxicity in CBZ-treated individuals. The objective of this study was to investigate the binding affinities of albumin with CBZ and CBZE, and to explore the influence of two competing over-the-counter medicines on the binding characteristics. CBZE was synthesized by epoxidation of CBZ and characterized using IR, NMR and mass spectrometry. The influence of paracetamol and ascorbic acid on the albumin complexes of CBZ and CBZE was investigated using absorption and IR spectrophotometry.ResultsProtein–ligand complexation produced progressive hyperchromic changes in 278 nm band of bovine serum albumin (BSA) with formation constants of 10.28–10.44 and 12.66–13.02 M−1 for CBZ and CBZE, respectively. Thermodynamic considerations confirmed both binding processes as endothermic, spontaneous and driven by hydrophobic interactions. The presence of ascorbic acid increased the binding constants of both CBZ-BSA and CBZE-BSA complexes by non-competitive interference mechanism. Similarly, paracetamol increased the affinity of CBZ for albumin but then competitively interfered with the CBZE-BSA complex. The ratio of albumin binding affinities of CBZ–CBZE varied from 0.81 in the absence of competing drug to 1.29 and 1.0 with paracetamol and ascorbic acid, respectively. IR study confirmed that both CBZ and CBZE induced a reduction from the 67.34% α-helical content of free BSA to 42.56 and 56.43%, respectively. Competitive binding in the presence of either paracetamol or ascorbic acid induced further reduction in the α-helical content of BSA in the complexes. The most extensive perturbation in the secondary structure of BSA (22.78% α-helical content) which was observed with CBZE-BSA complex in the presence of paracetamol is probably due to the increased interaction of the protein for the analgesic.ConclusionThe study has revealed potential interference of paracetamol or ascorbic acid with the albumin binding of carbamazepine and its major metabolite.

Molecularly imprinted polymer membranes based on single template for recognition and extraction of carbamazepine and its structurally analogues

In this work, a novel molecularly imprinted polymer membrane (MIPM) using oxcarbazepine (OXC) as the single template and polyvinylidene difluoride membrane as the subtract was fabricated for recognition and extraction of carbamazepine (CBZ) and its analogues including OXC, carbamazepine-10,11-epoxide (CBZE), and monohydroxy derivative 10, 11-dihydro-10-hydroxy carbamazepine (MHD). The prepared MIPMs were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, Brunaner-emmet-teller measurements and X-ray photoelectron spectroscopy, showing the successful construction of uniform and porous polymers on the surface of membranes. A series of adsorption affinity tests were investigated, indicating the prepared materials had specific recognition capacity and excellent stability as novel sorbents. The maximum static adsorption capacities of MIPMs towards OXC, CBZ, MHD or CBZE was 4.246, 3.621, 2.316, or 4.877 mg·g−1, respectively. The MIPMs showed reusability and reproducibility. The usability of MIPMs was evaluated by combining MIPMs extraction and high performance liquid chromatography detection for the determination of CBZ, CBZE, OXC and MHD in different matrices including methanol, normal saline, phosphate buffer solution, and plasma. The mean recovery of four target compounds in methanol, normal saline and phosphate buffer solution was more than 75 %, while the mean recovery of CBZ and CBZE in plasma was more than 80 %. The results demonstrated that the proposed MIPMs is very suitable for the determination of OXC, CBZ, MHD and/or CBZE in different matrices.

B-191 Development of a Simple, Robust, and Accurate LC-MS/MS Method for the Quantification of 17 Therapeutic Drugs: Initial Validation Results

Abstract Background Therapeutic Drug Monitoring (TDM) of Zonisamide (ZON), Felbamate (FELB), Lamotrigine (LMTR), 10-Hydroxycarbamazipine (OXCARB), Carbamazepine Epoxide (CARBEP), and Pentobarbital (PENTO) is essential in developing the regimen to produce the best clinical outcomes while monitoring for possible toxicity. Historically, both HPLC-UV and LC-MS/MS have been used for the quantification of these types of drugs. HPLC-UV is often subject to interferences and extended run times. Because of this, there has been a shift to LC-MS/MS methods which are often simple, fast, robust, and suffer from less interferences. Our objective was to develop a simple, robust, and accurate LC-MS/MS method to replace the HPLC-UV methodology. Method Serum (50 µL) and IS solution (100 µL; Zonisamide-13C6, Lamotrigine-13C,15N4, (±)-10,11-Dihydro-10-hychoxycarbamazepine-13C6, Carbamazepine-10,11-epoxide-13C6, Felbamate-D4, Pentobarbital-D5 in methanol with 0.5% acetic acid) were vortex mixed and centrifuged. Supernatant (50 µL) was mixed with 950 µL of water and vortexed mixed. Extract was injected on a Thermo Accucore C18 column. A quantifier and qualifier transition was monitored for all analytes. Multiple Reaction Monitoring (MRM) was performed in positive mode for all analytes except for PENTO (negative). Total chromatographic time for the 17 analytes is 7.31 min. Results No ion suppression, differential matrix effect, or interferences were observed. Analytical Measurement Range (AMR) data for the initial 6 analytes is presented in Table 1. The coefficient of variation (%CV) was <2.8% for ZON, <4.3% for FELB, <7.3% for LMTR, <3.8% for OXCARB, <3.0% for CARBEP, and <3.5% for PENTO. Method comparison with a previously validated method were acceptable (Table 1). Conclusion This simple, robust, and accurate LC-MS/MS method has been validated for the initial 6 anlytes and has been determined to be acceptable for clinical use. Validation of the remaining 11 analytes is ongoing (Pregabalin, Gabapentin, Levetiracetam, Ethosuximide, Lacosamide, Rufinamide, Primidone, Lamotrigine, Topiramate, Brivaracetam, and Perampanel).

Evaluating the efficacy of prototype antiseizure drugs using a preclinical pharmacokinetic approach.

Pharmacokinetics (PK) of a drug drive its exposure, efficacy, and tolerability. A thorough preclinical PK assessment of antiseizure medications (ASMs) is therefore essential to evaluate the clinical potential. We tested protection against evoked seizures of prototype ASMs in conjunction with analysis of plasma and brain PK as a proof-of-principle study to enhance our understanding of drug efficacy and duration of action using rodent seizure models. In vivo seizure protection assays were performed in adult male CF-1 mice and Sprague Dawley rats. Clobazam (CLB), N-desmethyl CLB (NCLB), carbamazepine (CBZ), CBZ-10,11-epoxide (CBZE), sodium valproate (VPA), and levetiracetam (LEV) concentrations were quantified in plasma and brain using liquid chromatography-tandem mass spectrometry. Mean concentrations of each analyte were calculated and used to determine PK parameters via noncompartmental analysis in Phoenix WinNonLin. NCLB concentrations were approximately 10-fold greater than CLB in mice. The antiseizure profile of CLB was partially sustained by NCLB in mice. CLB concentrations were lower in rats than in mice. CBZE plasma exposures were approximately 70% of CBZ in both mice and rats, likely contributing to the antiseizure effect of CBZ. VPA showed a relatively short half-life in both mice and rats, which correlated with a sharp decline in efficacy. LEV had a prolonged brain and plasma half-life, associated with a prolonged duration of action in mice. The study demonstrates the utility of PK analyses for understanding the seizure protection time course in mice and rats. The data indicate that distinct PK profiles of ASMs between mice and rats likely drive differences in drug efficacy between rodent models.

Covalent organic framework-based solid phase microextraction coupled with electrospray ionization mass spectrometry for sensitive screening and quantitative evaluation of carbamazepine and its metabolite in mice

Carbamazepine (CBZ) and its metabolite carbamazepine-10,11-epoxide (CBZEP) play vital role in the treatment of epilepsy. It is of great importance to develop a method for rapid and sensitive monitoring of CBZ and CBZEP due to their narrow therapeutic index. Herein, an imine-linked-based covalent organic framework was synthesized by using 1,3,5-tris (4-aminophenyl) benzene (TPB) and 1,3,5-triformylbenzene (TFB) (denoted as TPB-TFB-COF)，and applied as a solid-phase microextraction (SPME) probe for extracting CBZ and CBZEP. The TPB-TFB-COF showed large surface areas (371 m2 g−1), high regular porosity (1.23 nm) and extraordinary stability, which rendered it an ideal adsorbent for highly efficient enrichment of CBZ and CBZEP. Accordingly, an attractive strategy of the combination of the TPB-TFB–COF–based SPME probe and electrospray ionization mass spectrometry system (ESI/MS) was proposed for rapid screening and sensitive monitoring of CBZ and CBZEP. Under the optimized parameters, the developed method exhibited good linearity for CBZ and CBZEP in the range of 4–1000 μg L−1 with correlation coefficient (r) no less than 0.9953, and the corresponding limits of detection (LODs) were 0.4 and 2.5 μg L−1, respectively. Moreover, high enrichment factors (EFs, 202–351 folds) and satisfactory relative standard deviations (RSDs) of one probe (3.3–5.1%) and probe-to-probe (4.8–5.6%) were obtained. By using the proposed method, sensitive screening and quantitative evaluation of CBZ and CBZEP in mice whole blood and tissue homogenates were successfully achieved, indicating the promising applicability of the TPB-TFB–COF–SPME-AMIS as a powerful tool for drug monitoring.

Pharmaceutical and transformation products during unplanned water reuse: Insights into natural attenuation, plant uptake and human health impact under field conditions.

In urban and periurban areas, agricultural soils are often irrigated with surface water containing a complex mixture of contaminants due to wastewater treatment plant (WWTP) effluent discharges. The unplanned water reuse of these resources for crop irrigation can represent a pathway for contaminant propagation and a potential health risk due to their introduction in the food chain. The aim of this study is to provide data about the magnitude of attenuation processes and plant uptake, allowing for a reliable assessment of contaminant transfer among compartments and of the human health risk derived from unplanned water reuse activities. Target compounds are 25 pharmaceuticals, including transformation products (TPs). The field site is an agricultural parcel where maize is irrigated by a gravity-fed surface system supplied by the Jarama river, a water course strongly impacted by WWTP effluents. Throughout the 3-month irrigation period, irrigation water and water infiltrating through the vadose zone were sampled. The agricultural soil was collected before and after the irrigation campaign, and maize was sampled before harvesting. All selected compounds are detected in irrigation water (up to 12,867ng L-1). Metformin, two metamizole TPs and valsartan occur with the highest concentrations. For most pharmaceuticals, results demonstrate a high natural attenuation during soil infiltration (>60%). However, leached concentrations of some compounds can be still at concern level (>400ng L-1). A persistent behavior is observed for carbamazepine, carbamazepine epoxide and sulfamethoxazole. Pharmaceutical soil contents are in the order of ng g-1 and positively ionized compounds accumulate more effectively. Results also indicate the presence of a constant pool of drugs in soils. Only neutral and cationic pharmaceuticals are taken up in maize tissues, mainly in the roots. There is an insignificant threat to human health derived from maize consumption however, additional toxicity tests are recommended for 4AAA and acetaminophen.

ABCB1 c.3435C>T and EPHX1 c.416A>G polymorphisms influence plasma carbamazepine concentration, metabolism, and pharmacoresistance in epileptic patients.

The gene polymorphisms of ABCB1, EPHX1, and SCN1A were found to influence carbamazepine (CBZ) metabolism and resistance in epilepsy patients, but the relevance remains controversial. To reveal the relationships among the gene polymorphisms of ABCB1, EPHX1, SCN1A and the metabolism and resistance of CBZ, the databases of PubMed, EMBASE, Cochrane Library, Chinese National Knowledge Infrastructure, Chinese Science and Technique Journals, China Biology medicine disc and Wan Fang were retrieved for suitable studies up to April 2021. 18 studies containing 3293 epilepsy patients were included. The result revealed the gene polymorphism of ABCB1 c.3435C>T is significantly associated with altered concentration-dose ratios of CBZ (CDRCBZ) (CC vs. CT, OR=0.25 (95% CI: 0.08-0.42), P=0.004), and EPHX c.416A>G gene polymorphism may also significantly adjusted the concentration-dose ratios of carbamazepine-10, 11-trans dihydrodiol (CDRCBZD) (AA vs. GG, OR=0.48 (95% CI: 0.01-0.96), P=0.045; AG vs. GG, OR=0.68 (95% CI: 0.16-1.20), P=0.010, respectively) and the ratio of CBZD:carbamazepine-10,11-epoxide (CBZE) (CDRCBZD:CDRCBZE) (AG vs GG, OR=0.83 (95% CI: 0.31-1.36), P=0.002). Furthermore, ABCB1 c.3435C>T polymorphism was also observed to be significantly influenced CBZ resistance (CC vs TT, OR=1.78 (95% CI: 1.17-2.72), P=0.008; CT vs TT, OR=1.60 (95% CI: 1.12-2.30), P=0.01; CC+CT vs TT, OR=1.61 (95% CI: 1.15-2.26), P=0.006, respectively). Therefore, CBZ metabolism and resistance in patients with epilepsy may be adjusted by the gene polymorphisms of ABCB1 c.3435C>T and EPHX1 c.416A>G which provides the further scientific basis for clinical individualized therapy of epilepsy. However, larger sample size studies are still needed to provide further conclusive evidence.

Carbamazepine and carbamazepine-10, 11-epoxide therapeutic drug monitoring and biochemical and hematological evaluation in bipolar disorder outpatients

The objective of this study was to validate an analytical technique with HPLC-PDA for plasma measurement of carbamazepine (CBZ) and its metabolite carbamazepine-10, 11-epoxide (CBZ-E) for therapeutic monitoring (TM) of patients diagnosed with bipolar disorder (BD), as well as evaluating hematological and biochemical parameters of patients using CBZ. Sixteen patients registered with the Public Service of Psychiatry were selected. CBZ and CBZ-E measurements were performed with HPLC-PDA shimadzu LC-20 AT Prominence, under concentration gradient. Validation criteria: selectivity, linearity, precision, accuracy, recovery, stability. Hematological and biochemical tests were performed using conventional methods. As a result, it was obtained: accuracy >85% and precision <15%, good selectivity, robustness and stability, LOQ = 250 ng.mL-1 and HQL = 60,000 ng.mL-1. Among patients, 25% and 6.25% had CBZ and CBZ-E levels within the therapeutic range, respectively. There were hematological and biochemical changes related to the drug. The validated method is reliable for its intended purpose. TM proved to be extremely useful for detecting therapeutic failure.

Determination of serum carbamazepine and its metabolite by validated tandem mass spectrometric method and the effect of carbamazepine on various hematological and biochemical parameters

ObjectivesThe study aimed to develop a validated LC–MS / MS method for the measurement of carbamazepine and carbamazepine-10,11-epoxide (CBZE) levels, to compare the carbamazepine concentrations measured by AbSciex API 3200 LC–MS/MS and Beckman Coulter Emit® 2000 immunoassay and to investigate the effect of carbamazepine concentrations on various hematological and biochemical parameters. MethodsFor the measurement of carbamazepine and CBZE levels, a validated LC–MS / MS method was developed. Serum carbamazepine levels of patients were measured by AbSciex API 3200 LC–MS / MS and Beckman Coulter Emit® 2000 immunoassay. Biochemical, hematological parameters, and hormone levels were measured by Beckman-Coulter AU 5800 (Beckman Coulter, Brea, USA), Beckman Coulter LH 780 (Beckman Coulter, Miami, FL, USA), and Cobas 6000 (Roche Diagnostics, Germany) analyzers, respectively. ResultsThe imprecision values for all analytes were less than 7.0 %. The correlation coefficient between the methods was 0.981 (95 % confidence interval: 0.975 to 0.985). Linear regression analysis demonstrated highly significant associations of carbamazepine concentrations with albumin (B = −0.300, p = 0.040), calcium (B = −0.262, p = 0.004), phosphorus (B = −0.241, p = 0.022), WBC (B = −0.288, p = <0.001), PLT (B = −0.236, p = 0.003), RBC (B = −0.257, p = 0.001), NEU% (B = −0.289, p = <0.001), LYM% (B = −0.268, p = 0.001), D vitamini (B = −0.344, p = 0.006) levels. ConclusionsA robust, rapid, and simple method has been developed. Our study revealed that carbamazepine and its metabolite have a significant correlation and likely impact on bone metabolism, blood cell counts, serum protein, albumin levels, and electrolyte concentrations.

Bioavailability Improvement of Carbamazepine via Oral Administration of Modified-Release Amorphous Solid Dispersions in Rats.

The purpose of this study was to improve the bioavailability of carbamazepine (CBZ), a poorly water-soluble antiepileptic drug, via modified-release amorphous solid dispersions (mr-ASD) by a thin film freezing (TFF) process. Three types of CBZ-mr-ASD with immediate-, delayed-, and controlled-release properties were successfully prepared with HPMC E3 (hydrophilic), L100-55 (enteric), and cellulose acetate (CA, lipophilic), defined as CBZ-ir-ASD, CBZ-dr-ASD, and CBZ-cr-ASD, respectively. A dry granulation method was used to prepare CBZ-mr-ASD capsule formulations. Various characterization techniques were applied to evaluate the physicochemical properties of CBZ-mr-ASD and the related capsules. The drug remained in an amorphous state when encapsulated within CBZ-mr-ASD, and the capsule formulation progress did not affect the performance of the dispersions. In dissolution tests, the preparations and the corresponding dosage forms similarly showed typical immediate-, delayed-, and controlled-release properties depending on the solubility of the polymers. Moreover, single-dose 24 h pharmacokinetic studies in rats indicated that CBZ-mr-ASD significantly enhanced the oral absorption of CBZ compared to that of crude CBZ. Increased oral absorption of CBZ was observed, especially in the CBZ-dr-ASD formulation, which showed a better pharmacokinetic profile than that of crude CBZ with 2.63- and 3.17-fold improved bioavailability of the drug and its main active metabolite carbamazepine 10,11-epoxide (CBZ-E).

Comparison of high resolution mrm and sequential window acquisition of all theoretical fragment-ion acquisition modes for the quantitation of 48 wastewater-borne pollutants in lettuce

Screening of a large number of chemicals of emerging concern is highly desirable for the control of crops irrigated with reclaimed water since it is considered an alternative water source of great value. This study describes a high resolution mass spectrometry approach for developing methods for quantification in lettuce leaves of 48 different wastewater-borne pollutants (including analgesics and anti-inflammatories, anti-hypertensives, antifungal agents, lipid regulators, psychiatric drugs and stimulants, β-blockers, antibiotics, antimycotics, and sweeteners) frequently found in water resources. In this respect, a simple and fast QuEChERS-based method for the determination of contaminants in lettuce has been developed. During extraction, the use of formic acid was adopted to further improve the results of some problematic compounds (e.g., fenofibrate, furosemide, metronidazole, oxcarbazepine, sulfanilamide). High resolution multiple reaction monitoring (MRMHR) and SWATH acquisition were compared in term of accuracy, repeatability, sensitivity, linearity and matrix effect. Both methods provided similar recoveries between 80 and 120% in lettuce leaves, although sulfanilamide, ciprofloxacin, and sulfamethazine presenting values of 26.8, 27.8, and 28.4% in MRMHR and 25, 33.9, and 35% in SWATH, respectively. The effectiveness of a two-step cleanup on analyte recovery was also assessed and matrix effects were also taken into consideration during the method validation. The developed method allows the simultaneous quantitative analysis of 48 compounds (drug residues and metabolites) in lettuce leaves irrigated with treated wastewater for human consumption. Application of the present method to lettuce crops growth in controlled conditions showed the presence of 14 out 48 studied compounds with similar concentrations in both acquisition modes ranging from 3.3 and 1.3 ng g − 1 for climbazole (for MRMHR and SWATH, respectively) to 33.2 and 17.7 ng g − 1 for sulfamethazine. Drug residues such as carbamazepine (6.0 and 8.5 ng g − 1), and its metabolite carbamazepine epoxide (18.1 and 16.5 ng g − 1), frequently found in wastewater effluents, were also detected.

The effect of cannabidiol on the pharmacokinetics of carbamazepine in rats.

Carbamazepine (CBZ) is mainly metabolized by CYP3A4 into carbamazepine-10,11-epoxide (CBZE). Cannabidiol (CBD) is a potent inhibitor of the CYP3A family. The aim of this study is to determine the effect of acute and chronic administration of CBD on the pharmacokinetics of CBZ and CBZE. Male SD rats were assigned into four acute and four chronic groups: control (CBZ only), positive control (ketoconazole), low-dose cannabidiol (l-CBD), and high-dose cannabidiol (h-CBD). Acute CBD groups were administered a single dose of CBD, while chronic CBD groups were given multiple doses of CBD for 14days (q.d.) before CBZ administration. Plasma samples had been collected and analyzed for CBZ and CBZE, then their noncompartmental pharmacokinetic parameters before and after CBD administration were determined. The co-administration of a single l-CBD has significantly increased CBZ's [Formula: see text] by 53.1%. Furthermore, CBZE kinetics showed a significant decrease in Cmax by 31.8%. Acute h-CBD caused similar effects on CBZ's [Formula: see text] with 40.4% significant decrease in CBZE's Cmax, when compared to the control. Chronic h-CBD caused a significant decrease in CBZ's Cmax and [Formula: see text] by 75.3% and 65.7%, respectively. Besides, [Formula: see text] and Cmax of CBZE significantly decreased by 75.3% and 78.3%, respectively. These results demonstrated that the pharmacokinetics of CBZ and CBZE had been significantly affected by CBD. When CBD has been administered as a single dose, the effect is believed to be mainly caused by the inhibition of CBZ metabolism through CYP3A. The effect of chronic administration of CBD probably includes kinetic pathways other than the inhibition of CYP3A-dependent pathways. Graphical abstract.

Development of a monoclonal antibody-based immunochromatographic assay for the detection of carbamazepine and carbamazepine-10, 11-epoxide

In this study, haptens were designed to produce highly sensitive and specific monoclonal antibodies (mAb) against carbamazepine (CBZ) and its metabolite carbamazepine-10, 11-epoxide (CBZ-EP). According to the results of our competitive enzyme-linked immunosorbent assay (ic-ELISA), the half-maximum inhibitory concentration values for anti-CBZ and anti-CBZ-EP mAb were 0.18 and 0.59 ng/mL, respectively. An immunochromatographic assay (ICA) was developed for the determination of CBZ and CBZ-EP concentrations. This method can provide visible limits of detection ranging from 0.25 to 1 ng/mL, and cut-off limits ranging from 5 to 10 ng/mL, and takes 10 min to evaluate with the naked eye. Importantly, these observations were consistent with those obtained by ic-ELISA and liquid chromatography-mass spectrometry. The ICA assay represented a reliable, fast, and high-throughput method for the determination of CBZ and CBZ-EP in serum samples.

Simultaneous Determination of Phenobarbital, Phenytoin, Carbamazepine and Carbamazepine-10,11-epoxide in Plasma of Epileptic Patients

Background: Quantitative analyses of antiepileptic drugs are required in clinic and to rational dosage adjustment, the clinician needs the blood levels of these drugs. A high-performance liquid chromatography with spectrophotometric detection has been developed and validated for simultaneous determination of some antiepileptic drugs in plasma of patients with epilepsy. Methods: A simple procedure based on deproteinization by acetonitrile was used for pre-treatment of plasma samples. Liquid chromatographic analysis was carried out on a Nova-Pak® C18 analytical column, using a ternary mixture of potassium dihydrogen phosphate buffer (pH 6.0)-acetonitrile-2-propanol (63:22:15, v/v/v) as the mobile phase, at a flow rate of 1.0 mL min-1. Results: Calibration curves were linear over a range of 1–40 µg mL-1 for phenobarbital, 1–30 µg mL-1 for phenytoin, 0.3–15 µg mL-1 for carbamazepine and 0.5–6 µg mL-1 for carbamazepine epoxide. Conclusion: The simple sample pre-treatment, combined with the fast chromatographic run was used for the determination of antiepileptic drugs for a large number of patient samples.

Pharmacokinetic interaction of brivaracetam on other antiepileptic drugs in adults with focal seizures: Pooled analysis of data from randomized clinical trials

ObjectiveTo assess the effect of brivaracetam (BRV) on steady-state plasma concentrations of commonly prescribed antiepileptic drugs (AEDs). MethodsData were pooled from five randomized, double-blind, placebo-controlled efficacy studies (NCT00175929, NCT00175825, NCT00490035, NCT00464269, and NCT01261325) in which adults with refractory epilepsy, and receiving stable doses of 1–2 AEDs, initiated adjunctive treatment with BRV (or placebo) for up to 12 weeks, following a 4–8 week baseline period. Concentrations of carbamazepine, carbamazepine epoxide, clobazam, clonazepam, lacosamide, lamotrigine, levetiracetam, oxcarbazepine (MHD), phenobarbital, phenytoin, pregabalin, topiramate, valproic acid and zonisamide, were measured during baseline and during BRV or placebo evaluation periods. Log-transformed data for patients receiving BRV dosages of 50–200 mg/day (or placebo) were evaluated using repeated measures analysis of covariance. Geometric least-squares means ratios of respective AED concentrations (treatment vs baseline) and their 90% confidence intervals (CIs) were calculated. Relevant interaction of BRV on the respective AED was inferred if CIs were entirely outside of 0.80–1.25 limits. ResultsWithin the population for analysis (n = 1402), relevant interaction was observed for carbamazepine epoxide alone which increased up to 2-fold from baseline due to inhibition of epoxide hydrolase by BRV, and the effect size was not influenced by concomitant valproic acid. Relevant interaction was not observed for other AEDs. ConclusionIn adults with focal seizures, adjunctive BRV treatment does not affect plasma concentrations of the evaluated AEDs but increases carbamazepine epoxide metabolite. Carbamazepine dose reduction should be considered if tolerability issues arise.

The pharmacokinetics of oral carbamazepine in rats dosed using an automated drug delivery system.

Pharmacokinetics (PK) of antiseizure drugs differ considerably between rats and humans. Rodents require larger and more frequent doses to maintain therapeutic drug levels. This study uses the antiseizure drug (ASD) carbamazepine (CBZ) to validate the application of a previously described automated drug delivery system for delivering chronic oral medication to rats. Treatment-naive, male Sprague-Dawley rats were treated with oral CBZ, 75mg/kg every 6hours for 10days, via the automated feeder. Blood samples were collected on day 0 (acute), day 2 (steady-state), and day 9 (chronic) and used to measure plasma CBZ and carbamazepine-10,11-epoxide (CBZ-E) concentrations via high-performance liquid chromatography. The PK of CBZ and CBZ-E were modeled using Monolix v2018R1. The acute and chronic tolerability of CBZ was evaluated using the open field test. CBZ and CBZ-E concentrations were best described by a one-compartment parent-metabolite model with first-order absorption and elimination kinetics. Observed and predicted CBZ concentrations were maintained within the therapeutic window (4-12μg/mL) for the duration of the study. There was no change in open-field test activity following acute or chronic oral dosing of 75mg/kg CBZ compared to a pretreatment baseline (P>0.4). Oral administration of CBZ dosed q.i.d. in rats using an automated drug delivery system results in therapeutic concentrations of CBZ and its active metabolite. This study represents the first PK validation for this previously described preclinical drug delivery system.

Reduced Systemic and Brain Exposure with Inhibited Liver Metabolism of Carbamazepine After Its Long-Term Combination Treatment with Piperine for Epilepsy Control in Rats.

Carbamazepine (CBZ) with piperine, the active ingredient in black pepper, which is omnipresent in food and may be potentially used for epilepsy control owing to its anticonvulsant effects, can be coadministered to epileptic patients. Since piperine has previously demonstrated its inhibition of the CYP3A-mediated metabolism of CBZ to carbamazepine-10,11-epoxide (CBZE), the present study aimed to investigate the impact of piperine on CBZ pharmacokinetics (PKs) in rats and pharmacodynamics in zebrafish and mouse acute seizure models. Plasma and brain PKs were studied in rats after a single-dose or 2-week combined oral administration of piperine (3.5/35mg/kg, q.d.) and CBZ (40mg/kg, t.i.d.) by blood sampling and brain microdialysis. Although no PK change was noticed after a single coadministration, significantly decreased plasma and brain concentrations of CBZ and CBZE with inhibited rat liver Cyp3a2 were demonstrated after long-term combined administration. Our developed compartmental model for the PK characterization of CBZ and CBZE in the blood and brain further estimated that coadministration with high-dose piperine could lead to decreases of 26%, 35%, and 38% in bioavailability, metabolism, and brain uptake of CBZ, respectively. Regardless of the PK changes, a limited impact on the antiepileptic effect of CBZ was found after the coadministration of CBZ and piperine in the tested seizure models. In conclusion, single-dose cotreatment of CBZ and piperine did not result in any significant PK or pharmacodynamic interactions, whereas their long-term cotreatment could lead to inhibited liver metabolism and the markedly reduced systemic and brain exposure of CBZ and CBZE.