The Effect of Plasma Protein Binding on the Therapeutic Monitoring of Antiseizure Medications

Repurposing Antiepileptic Drugs for Cancer: A Promising Therapeutic Strategy

Epilepsy is a neurological disorder characterized by repeated convulsions. Antiepileptic drugs (AEDs) are the main course of therapy for epilepsy. These medications are given according to each patient's personal medical history and the types of seizures they suffer. They have been employed for decades to manage epilepsy, thus delivering relief from seizures through numerous mechanisms of action. Aside from their anticonvulsant attributes, current evidence suggests that certain AEDs may display potential inhibitory effects against cancer invasion and metastasis. This review explored the complicated interactions between the modes of action of AEDs and the pathways causing cancer, and the potential impact of AEDs on the invasion and metastasis of various forms of cancer, while addressing their associated side effects. For example, valproic acid inhibits histone deacetylase, causing hyperacetylation of genes, especially those regulating cell cycle, culminating in cell cycle arrest. Topiramate inhibits carbonic anhydrase, thus disrupting the acidic microenvironment needed for cancer cells to thrive. Lacosamide increases the slow inactivation of the voltage gated Na+ channel, thus inhibiting the growth, proliferation, and metastasis of many cancers. Although drug development is a complex task due to regulatory, intellectual property, and economic challenges, researchers are exploring drug repurposing tactics to overcome these challenges and to find new therapeutic alternatives for diseases like cancer. Thus, drug repurposing is considered among the most effective ways to develop drug candidates using novel properties and therapeutic characteristics, and this review also discusses these issues.

Factoring fu Variability Into Estimates of Unbound Drug Concentrations Negatively Biases the MIC Versus % Probability of Target Attainment Relationship of Antimicrobial Agents

The clinical breakpoint for a drug-pathogen combination reflects the drug susceptibility of the pathogen wild-type population, the location of the infection, the integrity of the host immune response, and the drug-pathogen pharmacokinetic (PK)/pharmacodynamic (PD) relationship. That PK/PD relationship, along with the population variability in drug exposure, is used to determine the probability of target attainment (PTA) of the PK/PD index at a specified minimum inhibitory concentration (MIC) for a selected target value. The PTA is used to identify the pharmacodynamic cutoff value (COPD), which is one of the three components used to establish the clinical breakpoint. A challenge encountered when defining the COPD is that the available PK information typically reflects total (free plus protein-bound) plasma concentrations. However, it is the unbound drug concentrations that exert the therapeutic effects and how the population fraction unbound (fu) incorporated into the COPD assessments can markedly influence the COPD. Factors examined included the estimated population fu mean (risk of bias) and the incorporation of estimated fu population variability into the Monte Carlo simulations when converting total to unbound plasma concentrations (risk of inflating variability). In this in silico study, the drug fu, systemic clearance, and the variability of both were altered so that the relative impact of each could be explored. We demonstrate that incorporating fu variability into the estimation of fAUCback can bias the COPD assessment and that the magnitude of bias reflects the relative variability in systemic clearance and fu.

Drug-Drug Interactions in Nosocomial Infections: An Updated Review for Clinicians

Prevention, assessment, and identification of drug-drug interactions (DDIs) represent a challenge for healthcare professionals, especially in nosocomial settings. This narrative review aims to provide a thorough assessment of the most clinically significant DDIs for antibiotics used in healthcare-associated infections. Complex poly-pharmaceutical regimens, targeting multiple pathogens or targeting one pathogen in the presence of another comorbidity, have an increased predisposition to result in life-threatening DDIs. Recognising, assessing, and limiting DDIs in nosocomial infections offers promising opportunities for improving health outcomes. The objective of this review is to provide clinicians with practical advice to prevent or mitigate DDIs, with the aim of increasing the safety and effectiveness of therapy. DDI management is of significant importance for individualising therapy according to the patient, disease status, and associated comorbidities.

Hollow Fiber-in-Syringe Equilibrium Sampling Through Supported-Liquid Membrane for Evaluation of Drug-Plasma Binding

Aim: The aim was to evaluate drug-plasma binding (DPB).by employing Hollow Fiber-in-Syringe Equilibrium Sampling Through Supported Liquid Membrane (HFiS ESTSLM) and RP-HPLC analysis.Materials & Methods: HFiS ESTSLM and RP-HPLC were used to evaluate DPB of three weak basic drugs (Metoprolol, Diphenhydramine, and Sildenafil) with differing hydrophilicity and binding ability to blood plasma.Results: The results exhibited an increasing drug-dependent magnitude of DPB for the three model drugs. This trend of DPB confirmed that HFiS ESTSLM has the required sensitivity for determining DPB of the drugs. The DPB was drug concentration-dependent within the tested drug concentration range, especially at high concentration.Conclusion: HFiS ESTSLM and RP-HPLC offered a simple, easy and cost-effective procedure to evaluate DPB of these basic drugs.

Population toxicokinetics of carbamazepine and its metabolite carbamazepine-10,11-epoxide in adults

BACKGROUND

Carbamazepine is one of the most commonly used antiseizure medications. Although carbamazepine pharmacokinetics in epileptic patients is well described, much less is known about these processes in the patients who experienced self-poisoning episode by this drug. Therefore, the aim of our investigation was to perform population toxicokinetics of carbamazepine and its metabolite carbamazepine-10,11-epoxide in adults.

RESEARCH DESIGN AND METHODS

Software program NONMEM and the ADVAN2 TRANS2 subroutine were used for establishing a population toxicokinetic model for the estimation of clearance and volume of distribution based on of the sum values of carbamazepine and carbamazepine-10,11-epoxide concentrations.

RESULTS

Our results indicated that the adult patients' ability to eliminate carbamazepine and carbamazepine-10,11-epoxide following acute carbamazepine self-poisoning was strongly associated with the high levels of CRP and ASP, as well as by the treatment with sedation.

CONCLUSIONS

Our study should provide better understanding of the toxicokinetics of carbamazepine taken in overdose and better management of patient population admitted to hospital.

Effect of Age, Comedications, and CYP3A4/5 Polymorphisms on Perampanel Exposure in Chinese Pediatric Patients With Epilepsy

Perampanel (PER) is a new type of antiseizure medication used for partial or generalized seizures. However, the plasma concentration shows obvious individual variability in children. The present study aims to ascertain the effect of age, comedications, and cytochrome P450 (CYP) 3A4/5 polymorphisms on PER exposure in Chinese pediatric patients with epilepsy. Clinical data were retrospectively collected in a tertiary children's hospital medical records system from January 2021 to December 2022. The influence factors on the daily dose, plasma concentration, and concentration-to-dose ratio (CDR) of PER were investigated. A total of 135 pediatric patients with 178 blood samples were involved. With a median daily dose of 4.0 mg (interquartile range, 3.0-5.0 mg), the median plasma concentration was 409.4 ng/mL (interquartile range, 251.7-639.4 ng/mL). The CDR in patients aged less than 4 years was significantly decreased by 48.0% and 39.1% compared with those aged 4-11 years and 12 years or older, respectively. Enzyme inducers significantly decreased the CDR of PER by 34.5%, while valproic acid showed an increase of 71.7%. In addition, genotype CYP3A5*3/*3 carriers presented a significant increase of 21.5% compared to the CYP3A5*1/*3 expresser. No correlations were observed between the CDR and CYP3A4∗1G polymorphism. PER showed high variations in individual plasma concentrations. Age younger than 4 years, comedication with enzyme inducers or valproic acid, and possession of the CYP3A5*3 genotype potentially predicted PER exposure in pediatric patients with epilepsy.

Differential effects of FcRn antagonists on the subcellular trafficking of FcRn and albumin

The homeostasis of IgG is maintained by the neonatal Fc receptor, FcRn. Consequently, antagonism of FcRn to reduce endogenous IgG levels is an emerging strategy for treating antibody-mediated autoimmune disorders using either FcRn-specific antibodies or an engineered Fc fragment. For certain FcRn-specific antibodies, this approach has resulted in reductions in the levels of serum albumin, the other major ligand transported by FcRn. Cellular and molecular analyses of a panel of FcRn antagonists have been carried out to elucidate the mechanisms leading to their differential effects on albumin homeostasis. These analyses have identified 2 processes underlying decreases in albumin levels during FcRn blockade: increased degradation of FcRn and competition between antagonist and albumin for FcRn binding. These findings have potential implications for the design of drugs to modulate FcRn function.

Pre-treatment risk predictors of valproic acid-induced dyslipidemia in pediatric patients with epilepsy

Background: Valproic acid (VPA) stands as one of the most frequently prescribed medications in children with newly diagnosed epilepsy. Despite its infrequent adverse effects within therapeutic range, prolonged VPA usage may result in metabolic disturbances including insulin resistance and dyslipidemia. These metabolic dysregulations in childhood are notably linked to heightened cardiovascular risk in adulthood. Therefore, identification and effective management of dyslipidemia in children hold paramount significance. Methods: In this retrospective cohort study, we explored the potential associations between physiological factors, medication situation, biochemical parameters before the first dose of VPA (baseline) and VPA-induced dyslipidemia (VID) in pediatric patients. Binary logistic regression was utilized to construct a predictive model for blood lipid disorders, aiming to identify independent pre-treatment risk factors. Additionally, The Receiver Operating Characteristic (ROC) curve was used to evaluate the performance of the model. Results: Through binary logistic regression analysis, we identified for the first time that direct bilirubin (DBIL) (odds ratios (OR) = 0.511, p = 0.01), duration of medication (OR = 0.357, p = 0.009), serum albumin (ALB) (OR = 0.913, p = 0.043), BMI (OR = 1.140, p = 0.045), and aspartate aminotransferase (AST) (OR = 1.038, p = 0.026) at baseline were independent risk factors for VID in pediatric patients with epilepsy. Notably, the predictive ability of DBIL (AUC = 0.690, p < 0.0001) surpassed that of other individual factors. Furthermore, when combined into a predictive model, incorporating all five risk factors, the predictive capacity significantly increased (AUC = 0.777, p < 0.0001), enabling the forecast of 77.7% of dyslipidemia events. Conclusion: DBIL emerges as the most potent predictor, and in conjunction with the other four factors, can effectively forecast VID in pediatric patients with epilepsy. This insight can guide the formulation of individualized strategies for the clinical administration of VPA in children.

Behind the Curtain: Therapeutic Drug Monitoring of Psychotropic Drugs from a Laboratory Analytical Perspective

PURPOSE

Therapeutic drug monitoring (TDM) is a well-established tool for guiding psychopharmacotherapy and improving patient care. Despite their established roles in the prescription of psychotropic drugs, the "behind the curtain" processes of TDM requests are invariably obscure to clinicians, and literature addressing this topic is scarce.

METHODS

In the present narrative review, we provide a comprehensive overview of the various steps, starting from requesting TDM to interpreting TDM findings, in routine clinical practice. Our goal was to improve clinicians' insights into the numerous factors that may explain the variations in TDM findings due to methodological issues.

RESULTS

We discussed challenges throughout the TDM process, starting from the analyte and its major variation forms, through sampling procedures and pre-analytical conditions, time of blood sampling, sample matrices, and collection tubes, to analytical methods, their advantages and shortcomings, and the applied quality procedures. Additionally, we critically reviewed the current and future advances in the TDM of psychotropic drugs.

CONCLUSIONS

The "behind the curtain" processes enabling TDM involve a multidisciplinary team, which faces numerous challenges in clinical routine. A better understanding of these processes will allow clinicians to join the efforts for achieving higher-quality TDM findings, which will in turn improve treatment effectiveness and safety outcomes of psychotropic agents.

Benefits of bone marrow mesenchymal stem cells compared to their conditioned medium in valproic acid-induced autism in rats

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by repetitive behaviors, a limited range of activities, and deficiencies in social communications. Bone marrow mesenchymal stem cells (BM-MSCs), which secrete factors that stimulate surrounding microenvironment, and BM-MSCs conditioned medium (BM-MSCs-CM), which contains cell-secreted products, have been speculated to hold potential as a therapy for ASD. This study aimed to compare the therapeutic effects of BM-MSCs and BM-MSCs-CM on behavioral and microglial changes in an animal model of autism induced by valproic acid (VPA).

METHODS AND RESULTS

Pregnant Wistar rats were administered by VPA at a dose of 600 mg/kg at 12.5 days post-conception. After birth, male pups were included in the study. At 6 weeks of age, one group of rats received intranasal administration of BM-MSCs, while another group received BM-MSCs-CM. The rats were allowed to recover for 2 weeks. Behavioral tests, quantitative real-time polymerase chain reaction (qRT-PCR), and immunohistochemistry were performed. Both BM-MSCs and BM-MSCs-CM administration significantly improved some behavioral deficits. Furthermore, these treatments notably reduced Iba-1 marker associated with microgliosis. Additionally, there was a significant reduction in the expression of pro-inflammatory cytokines IL-1β and IL-6, and an increase in the levels of the anti-inflammatory cytokine IL-10 in rats administered by BM-MSCs and BM-MSCs-CM.

CONCLUSIONS

Post-developmental administration of BM-MSCs and BM-MSCs-CM can ameliorate prenatal neurodevelopmental deficits, restore cognitive and social behaviors, and modulate microglial and inflammatory markers. Results indicated that the improvement rate was higher in the BM-MSCs group than BM-MSCs-CM group.

Pharmacogenetics of Carbamazepine: A Systematic Review on CYP3A4 and CYP3A5 Polymorphisms

BACKGROUND AND OBJECTIVE

The association between carbamazepine (CBZ) metabolism and resistance in epilepsy and the genetic polymorphisms of CYP3A5 (rs776746 and rs15524) and CYP3A4 (rs2242480, rs2740574, rs35599367, rs12721627, and rs28371759) has been the subject of previous investigations with controversial results. Hence, we conducted a systematic review to assess the potential link between these polymorphisms and CBZ metabolism and resistance.

METHODS

Identifying relevant studies was carried out by searching PubMed, Scopus, PharmGKB, EPIGAD, and PHARMAADME databases up until June 2023. The studies included in our analysis investigated the connection between CYP3A5 (rs776746 and rs15524) and CYP3A4 (rs2242480, rs2740574, rs35599367, rs12721627, and rs28371759) polymorphisms and CBZ metabolism and resistance.

RESULTS

This review included a total of 23 studies and more than 2177 epilepsy patients. It was found that the CYP3A4 (rs12721627 and rs28371759) polymorphisms are associated with reduced catalytic activity, whereas the CYP3A4 (rs2740574) polymorphism is linked to lower levels of CBZ-diol and decreased activity. It was also observed that the CYP3A5 (rs776746) polymorphism influences the dose-adjusted plasma levels of CBZ.

CONCLUSION

Although these findings highlight the impact of genetic variations in the CYP3A4 and CYP3A5 genes on CBZ pharmacokinetics and pharmacodynamics, further studies across diverse populations are essential to enhance personalized epilepsy therapy in clinical settings.

Gabapentin-Associated Movement Disorders: A Literature Review

BACKGROUND

Gabapentin (GBP)-induced movement disorders (MDs) are under-recognized adverse drug reactions. They are commonly not discussed with patients, and their sudden occurrence can lead to misdiagnosis. This literature review aims to evaluate the clinical-epidemiological profile, pathological mechanisms, and management of GBP-associated MD.

METHODS

Two reviewers identified and assessed relevant reports in six databases without language restriction between 1990 and 2023.

RESULTS

A total of 99 reports of 204 individuals who developed a MD associated with GBP were identified. The MDs encountered were 135 myoclonus, 22 dyskinesias, 7 dystonia, 3 akathisia, 3 stutterings, 1 myokymia, and 1 parkinsonism. The mean and median ages were 54.54 (SD: 17.79) and 57 years (age range: 10-89), respectively. Subjects were predominantly male (53.57%). The mean and median doses of GBP when the MD occurred were 1324.66 (SD: 1117.66) and 1033 mg/daily (GBP dose range: 100-9600), respectively. The mean time from GBP-onset to GBP-associated MD was 4.58 weeks (SD: 8.08). The mean recovery time after MD treatment was 4.17 days (SD: 4.87). The MD management involved GBP discontinuation. A total of 82.5% of the individuals had a full recovery in the follow-up period.

CONCLUSIONS

Myoclonus (GRADE A) and dyskinesia (GRADE C) were the most common movement disorders associated with GBP.

Pharmacological aspects of antiseizure medications: From basic mechanisms to clinical considerations of drug interactions and use of therapeutic drug monitoring

Antiseizure medications (ASMs) are the cornerstone of treatment for patients with epilepsy. Several new ASMs have recently been introduced to the market, making it possible to better tailor the treatment of epilepsy, as well as other indications (psychiatry and pain disorders). For this group of drugs there are numerous pharmacological challenges, and updated knowledge on their pharmacodynamic and pharmacokinetic properties is, therefore, crucial for an optimal treatment outcome. This review focuses on educational approaches to the following learning outcomes as described by the International League Against Epilepsy (ILAE): To demonstrate knowledge of pharmacokinetics and pharmacodynamics, drug interactions with ASMs and with concomitant medications, and appropriate monitoring of ASM serum levels (therapeutic drug monitoring, TDM). Basic principles in pharmacology, pharmacokinetic variability, and clinically relevant approaches to manage drug interactions are discussed. Furthermore, recent improvements in analytical technology and sampling are described. Future directions point to the combined implementation of TDM with genetic panels for proper diagnosis, pharmacogenetic tests where relevant, and the use of biochemical markers that will all contribute to personalized treatment. These approaches are clinically relevant for an optimal treatment outcome with ASMs in various patient groups.

A novel method for predicting the unbound valproic acid concentration

In this study, we constructed a prediction formula for unbound valproic acid (VPA) concentration that was more accurate and widely applicable than previously reported formulae. A total of 136 datasets from 75 patients were analyzed retrospectively. The median of free fraction of VPA was 0.16 (interquartile range: 0.07; range: 0.07-0.45). The parameter that combined total VPA concentration (C_tVPA) and serum albumin (SA), (C_tVPA [μM] - 2 × SA [μM]), was significantly related to the free fraction of VPA (r = 0.76, p < 0.001). We constructed a combined parameter-based prediction formula for unbound VPA concentration. Analysis using external datasets from patients without severe renal failure showed that the prediction errors of the unbound VPA concentration were lower than those of previously reported formulae. Although the previous formulae showed large prediction errors, especially in the specific range of C_tVPA values, the constructed formula showed a weak trend with C_tVPA or SA. The formula based on (C_tVPA [μM] - 2 × SA [μM]) had high prediction accuracy and wide applicability in predicting the unbound VPA concentration in patients without severe renal failure.

Autism Spectrum Disorder: Neurodevelopmental Risk Factors, Biological Mechanism, and Precision Therapy

Autism spectrum disorder (ASD) is a heterogeneous, behaviorally defined neurodevelopmental disorder. Over the past two decades, the prevalence of autism spectrum disorders has progressively increased, however, no clear diagnostic markers and specifically targeted medications for autism have emerged. As a result, neurobehavioral abnormalities, neurobiological alterations in ASD, and the development of novel ASD pharmacological therapy necessitate multidisciplinary collaboration. In this review, we discuss the development of multiple animal models of ASD to contribute to the disease mechanisms of ASD, as well as new studies from multiple disciplines to assess the behavioral pathology of ASD. In addition, we summarize and highlight the mechanistic advances regarding gene transcription, RNA and non-coding RNA translation, abnormal synaptic signaling pathways, epigenetic post-translational modifications, brain-gut axis, immune inflammation and neural loop abnormalities in autism to provide a theoretical basis for the next step of precision therapy. Furthermore, we review existing autism therapy tactics and limits and present challenges and opportunities for translating multidisciplinary knowledge of ASD into clinical practice.

Effect of ancillary ligand on DNA and protein interaction of the two Zn (II) and Co (III) complexes: experimental and theoretical study

In the present work we have developed one mononuclear Zn(II) complex [Zn(L)(H2O)] (Complex 1) by utilizing a tetracoordinated ligand H₂L, formed by simple condensation of 2, 2 dimethyl 1,3 diamino propane and 3- ethoxy salicylaldehyde and one newly designed mononuclear Co (III) complex [Co(L)(L1)] (complex 2) by utilizing (H₂L) and 3- ethoxy salicylaldehyde(HL1) as an ancillary ligand. The newly developed complex 2 have been spectroscopically characterized. An interesting phenomenon has been noticed that in presence of ancillary ligand, the solubility in buffer solution and the thermal stability of complex 2 comparatively increases than 1. To check the effect of ancillary ligand, present in complex 2 towards the DNA and HSA binding efficacy, both the complexes have been taken into consideration to inspect their binding potentiality with the macromolecules. The 'on', 'off' fluorescence changes in presence of DNA and HSA, the binding constant values, obtained from electronic spectral titration, iodide induced quenching, competitive binding assay, circular dichroism (CD) spectral titration, time resolved fluorescence experiment unambiguously assure the better binding efficacy of complex 2 with the signal of minor groove binding mode with DNA along with no significant conformational changes of the macromolecules. The strong and spontaneous binding of complex 2 with CT-DNA is further supported by the Isothermal Titration Calorimetry (ITC) study. Furthermore TDDFT calculation of DNA with and without complex 2 significantly authorize the formation of complex 2-DNA adduct during the association. Finally Molecular Docking study properly verifies the experimental findings and provides justified explanation behinds experimental findings.

Review of preclinical data of PF-07304814 and its active metabolite derivatives against SARS-CoV-2 infection

Main protease (M^pro) is a superior target for anti-SARS-COV-2 drugs. PF-07304814 is a phosphate ester prodrug of PF-00835231 that is rapidly metabolized into the active metabolite PF-00835231 by alkaline phosphatase (ALP) and then suppresses SARS-CoV-2 replication by inhibiting M^pro. PF-07304814 increased the bioavailability of PF-00835231 by enhancing plasma protein binding (PPB). P-glycoprotein (P-gp) inhibitors and cytochrome P450 3A (CYP3A) inhibitors increased the efficacy of PF-00835231 by suppressing its efflux from target cells and metabolism, respectively. The life cycle of SARS-CoV-2 is approximately 4 h. The mechanisms and efficacy outcomes of PF-00835231 occur simultaneously. PF-00835231 can inhibit not only cell infection (such as Vero E6, 293T, Huh-7.5, HeLa^{+angiotensin-converting enzyme 2 (ACE2)}, A549^+ACE2, and MRC-5) but also the human respiratory epithelial organ model and animal model infection. PF-07304814 exhibits a short terminal elimination half-life and is cleared primarily through renal elimination. There were no significant adverse effects of PF-07304814 administration in rats. Therefore, PF-07304814 exhibits good tolerability, pharmacology, pharmacodynamics, pharmacokinetics, and safety in preclinical trials. However, the Phase 1 data of PF-07304814 were not released. The Phase 2/3 trial of PF-07304814 was also suspended. Interestingly, the antiviral activities of PF-00835231 derivatives (compounds 5–22) are higher than, similar to, or slightly weaker than those of PF-00835231. In particular, compound 22 exhibited the highest potency and had good safety and stability. However, the low solubility of compound 22 limits its clinical application. Prodrugs, nanotechnology and salt form drugs may solve this problem. In this review, we focus on the preclinical data of PF-07304814 and its active metabolite derivatives to hopefully provide knowledge for researchers to study SARS-CoV-2 infection.

Advances And Challenges In Using Nirmatrelvir And Its Derivatives Against Sars-Cov-2 Infection

On 22 December 2021, the United States Food and Drug Administration (FDA) approved the first M^pro inhibitor, i.e., oral antiviral nirmatrelvir (PF-07321332)/ritonavir (Paxlovid), for the treatment of early severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Nirmatrelvir inhibits SARS-CoV-2 infection, but high doses or long-term treatment may cause embryonic developmental toxicity and changes in host gene expression. The chiral structure of nirmatrelvir plays a key role in its antiviral activity. Ritonavir boosts the efficacy of nirmatrelvir by inactivating cytochrome P450 3A4 (CYP3A4) expression and occupying the plasma protein binding sites. Multidrug resistance protein 1 (MDR1) inhibitors may increase the efficacy of nirmatrelvir. However, paxlovid has many contraindications. Some patients treated with paxlovid experience a second round of coronavirus disease 2019 (COVID-19) symptoms soon after recovery. Interestingly, the antiviral activity of nirmatrelvir metabolites, such as compounds 12−18, is similar to or higher than that of nirmatrelvir. Herein, we review the advances and challenges in using nirmatrelvir and its derivatives with the aim of providing knowledge to drug developers and physicians in the fight against COVID-19.

Development and Validation of a UHPLC-MS/MS-Based Method to Quantify Cenobamate in Human Plasma Samples

Cenobamate (CNB) is the newest antiseizure medication (ASM) approved by the FDA in 2019 to reduce uncontrolled partial-onset seizures in adult patients. Marketed as Xcopri in the USA or Ontozry in the EU (tablets), its mechanism of action has not been fully understood yet; however, it is known that it inhibits voltage-gated sodium channels and positively modulates the aminobutyric acid (GABA) ion channel. CNB shows 88% of oral bioavailability and is responsible for modifying the plasma concentrations of other co-administered ASMs, such as lamotrigine, carbamazepine, phenytoin, phenobarbital and the active metabolite of clobazam. It also interferes with CYP2B6 and CYP3A substrates. Nowadays, few methods are reported in the literature to quantify CNB in human plasma. The aim of this study was to develop and validate, according to the most recent guidelines, an analytical method using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) to evaluate CNB dosage in plasma samples. Furthermore, we provided a preliminary clinical application of our methodology by evaluating the pharmacokinetic parameters of CNB in two non-adult patients. Plasma levels were monitored for two months. Preliminary data showed a linear increase in plasma CNB concentrations, in both patients, in agreement with the increase in CNB dosage. A seizure-free state was reported for both patients at the dose of 150 mg per day.

Therapeutic drug monitoring of perampanel in children diagnosed with epilepsy: Focus on influencing factors on the plasma concentration-to-dose ratio

OBJECTIVE

This study aimed to investigate the efficacy and tolerability of perampanel (PER) therapy and to optimize a specific plasma reference range for PER in children. Another major aim was to evaluate the potential determinators of PER concentration.

METHODS

Concentrations obtained from 80 children were analyzed for routine therapeutic drug monitoring (TDM) between 2021 and 2022. We retrospectively reviewed the clinical data of these patients and assessed the efficacy at 3 months after treatment initiation. Trough concentration-to-dose ratio (C₀ /Dose ratio) of PER was compared among patients on various potential influencing factors.

RESULTS

A 3-month PER therapy produced a ≥50% reduction in seizure frequency in 58.8% of patients. Twelve patients reported at least one adverse effect (AE), mainly dizziness. The monitoring data showed that the median C₀ was 325.5 ng/mL. Under maintenance dosages, approximately 75% of the C₀ values were 180.0-610.0 ng/mL. The C₀ /Dose ratio in patients aged 1 to <4 was significantly lower by twofold than in those aged 4 to ≤12 years (P = 0.001). Enzyme-inducing ASMs (EIASMs) decreased the C₀ /Dose ratio of PER by 25.9% (P = 0.165). In addition, seizure frequency reduction in responders was achieved at a median PER C₀ value of 357 ng/mL, which was similar to the value of 314 ng/mL found in nonresponders (P = 0.288). No significant difference was found in PER C₀ values between patients with and without AEs (P = 0.082).

SIGNIFICANCE

In this study, PER treatment showed acceptable efficacy and tolerance in Chinese children with epilepsy. Contributing factors like age to variable C₀ /Dose ratios were identified, and complex PER-ASMs interactions were observed. Notably, the reference range, that is, 180.0-610.0 ng/mL, for routine PER monitoring may be more applicable for them. Routine TDM should be considered a positive attempt to manage the effectiveness and safety of PER.

Biosensors technology for anti-epileptic drugs

A broad group of antiepileptic drugs (AEDs) often controls the frequency of seizures. Given the variability of pharmacokinetics, narrow target range, and the difficulty of identifying signs of toxicity from laboratory responses, therapeutic monitoring of AEDs plays a vital role in optimizing drug administration. Nanomaterials, especially biosensor-based methods, can facilitate the analysis of these agents with unique advantages such as rapid analysis, sensitivity, selectivity, and low cost. This review describes recent advances in biosensors developed to analyze AEDs. First, we described common electrochemical measurement techniques and types of deposited electrode substrates. Additionally, various chemical and biological modifiers to improve the sensitivity and selectivity of the sensor have been categorized and briefly described. Finally, the prospects for developing an electrochemical platform for quantifying AEDs are presented.

Clinical Significance of Serum Albumin and Implications of FcRn Inhibitor Treatment in IgG-Mediated Autoimmune Disorders

Serum albumin (SA), the most abundant soluble protein in the body, maintains plasma oncotic pressure and regulates the distribution of vascular fluid and has a range of other important functions. The goals of this review are to expand clinical knowledge regarding the functions of SA, elucidate effects of dysregulated SA concentration, and discuss the clinical relevance of hypoalbuminemia resulting from various diseases. We discuss potential repercussions of SA dysregulation on cholesterol levels, liver function, and other processes that rely on its homeostasis, as decreased SA concentration has been shown to be associated with increased risk for cardiovascular disease, hyperlipidemia, and mortality. We describe the anti-inflammatory and antioxidant properties of SA, as well as its ability to bind and transport a plethora of endogenous and exogenous molecules. SA is the primary serum protein involved in binding and transport of drugs and as such has the potential to affect, or be affected by, certain medications. Of current relevance are antibody-based inhibitors of the neonatal Fc receptor (FcRn), several of which are under clinical development to treat immunoglobulin G (IgG)-mediated autoimmune disorders; some have been shown to decrease SA concentration. FcRn acts as a homeostatic regulator of SA by rescuing it, as well as IgG, from intracellular degradation via a common cellular recycling mechanism. Greater clinical understanding of the multifunctional nature of SA and the potential clinical impact of decreased SA are needed; in particular, the potential for certain treatments to reduce SA concentration, which may affect efficacy and toxicity of medications and disease progression.

Carbamazepine Increases the Risk of Sudden Cardiac Arrest by a Reduction of the Cardiac Sodium Current

Aim: To assess the risk of sudden cardiac arrest (SCA) associated with the use of carbamazepine (CBZ) and establish the possible underlying cellular electrophysiological mechanisms.

Methods: The SCA risk association with CBZ was studied in general population cohorts using a case–control design (n = 5,473 SCA cases, 21,866 non-SCA controls). Effects of 1–100 µM CBZ on action potentials (APs) and individual membrane currents were determined in isolated rabbit and human cardiomyocytes using the patch clamp technique.

Results: CBZ use was associated with increased risk of SCA compared with no use (adjusted odds ratio 1.90 [95% confidence interval: 1.12–3.24]). CBZ reduced the AP upstroke velocity of rabbit and human cardiomyocytes, without prominent changes in other AP parameters. The reduction occurred at ≥30 µM and was frequency-dependent with a more pronounced reduction at high stimulus frequencies. The cardiac sodium current (I_Na) was reduced at ≥30 μM; this was accompanied by a hyperpolarizing shift in the voltage-dependency of inactivation. The recovery from inactivation was slower, which is consistent with the more pronounced AP upstroke velocity reduction at high stimulus frequencies. The main cardiac K⁺ and Ca²⁺ currents were unaffected, except reduction of L-type Ca²⁺ current by 100 µM CBZ.

Conclusion: CBZ use is associated with an increased risk of SCA in the general population. At concentrations of 30 µM and above, CBZ reduces AP upstroke velocity and I_Na in cardiomyocytes. Since the concentration of 30 µM is well within the therapeutic range (20–40 µM), we conclude that CBZ increases the risk of SCA by a reduction of the cardiac I_Na.