A UPLC-MS/MS method for simultaneous determination of nine antiepileptic drugs in human plasma and its application in TDM

Development and validation of an UPLC-MS/MS method with polarity switching for simultaneous determination of 14 antiepileptic drugs and 2 metabolites in human serum

Currently, treatment with antiepileptic drugs (AEDs) is still the first choice for epileptic patients, while monitoring their blood concentrations is undoubtedly beneficial for minimizing their adverse side effects and optimizing their therapeutic effects. In this study, an ultra-high performance liquid chromatography coupled with tandem mass spectrometry with polarity switching was developed and validated for simultaneous determination of 14 AEDs and 2 active metabolites in human serum. Olanzapine was selected as the internal standard. One-step protein precipitation using methanol containing 0.05 % formic acid was used to treat sample, and the supernatant was injected for analysis without further evaporation and reconstitution. Chromatographic separation was performed on an Aglient Zorbax Eclipse Plus C18 (50 mm × 2.1 mm, 1.8 μm) column with gradient methanol and 0.1 % formic acid in water as mobile phase. Multi-reaction monitoring was performed for quantification of 16 analytes in polarity switching mode. Matrix-matched calibration curves of 16 analytes presented good linearity within the test concentration range (r > 0.99). The intra- and inter-run accuracies and precisions at the lower limit of quantification, and low, medium and high quality control levels were all less than 20 % or 15 %, respectively. The extraction recovery, matrix effect, and stability were all acceptable under detected conditions. Finally, this method was successfully applied in the quantitation of target analytes in the serum of patients received AEDs.

Diazepam nanocapsules as an alternative for sleep induction: Development study and toxicity assessment

Diazepam (DZP) is a sedative medication prescribed to treat anxiety and as a sleep inducer, although its residual effects are unfavorable to patients. Nanotechnology represents a tool to improve the pharmacological characteristics of drugs, reducing their side effects. This study aimed to develop and characterize DZP nanocapsules and to evaluate their toxicity in alternative models and the hypnotic-sedative effect in mice. Nanocapsules were prepared by the nanoprecipitation method and properly characterized. Long-term and accelerated stability studies were performed. The in vitro release profile was determined by diffusion in Franz cells. The safety of the formulation was evaluated in the Caenorhabditis elegans (C. elegans) and the oral acute toxicity in mice. Pharmacological evaluation was performed using thiopental-induced sleeping time. DZP was successfully incorporated into Poly-(ɛ-caprolactone) (PCL) nanocapsules, with high entrapment efficiency. The nanocapsule did not affect the development or survival of C. elegans, different from the free drug, which affected the nematode development at the higher tested dose. No signs of toxicity, nor body mass or feed consumption changes were observed during the 14 days evaluated. Finally, this innovative formulation carrying DZP can produce a hypnotic-effect at a reduced dose compared to the free drug, with no toxicity in alternative models.

UPLC-MS/MS determination of 71 neuropsychotropic drugs in human serum

In this study, a UPLC-MS/MS method was developed for the rapid detection of 71 neuropsychotropic drugs in human serum for drug concentration monitoring and toxicity screening. The analytes were separated from the biological matrix by protein precipitation using a methanol-acetonitrile solvent mixture. The chromatographic separation was performed on a Kromasil ClassicShell C18 column (2.1*50 mm, 2.5 μ m) with gradient elution using acetonitrile-0.2 % acetic acid and 10 mM ammonium acetate as the mobile phases (flow rate 0.4 mL/min, column temperature 40 °C, injection volume 5 μL). An electrospray ion source in both positive and negative ion modes with multiple ion monitoring was used. The total run time was 6 min. All compounds were quantified using the isotope internal standard method. Totally, 71 drugs were detected within their linear ranges with correlation coefficients greater than 0.990. The intra- and inter-batch precision relative standard deviations (RSDs) for the low, medium, and high concentration points were less than 15 %, with an accuracy of 90%-110 %. All compounds except Moclobemide N-oxindole are stabilised within 7 days. The relative matrix effect results for each analyte were within ±20 % of the requirements. The method is validated according to Clinical and Laboratory Standards Institute guidelines, easy to use, and has a low cost.

Simple HPLC-UV Method for Therapeutic Drug Monitoring of 12 Antiepileptic Drugs and Their Main Metabolites in Human Plasma

The objective of the present report was to develop and validate a simple, selective, and reproducible high-performance liquid chromatography method with UV detection suitable for routine therapeutic drug monitoring of the most commonly used antiepileptic drugs and some of their metabolites. Simple precipitation of plasma proteins with acetonitrile was used for sample preparation. 10,11-dihydrocarbamazepine was used as an internal standard. Chromatographic separation of the analytes was achieved by gradient elution on a Phenyl-Hexyl column at 40 °C, using methanol and potassium phosphate buffer (25 mM; pH 5.1) as a mobile phase. The method was validated according to the FDA guidelines for bioanalytical method validation. It showed to be selective, accurate, precise, and linear over the concentration ranges of 1-50 mg/L for phenobarbital, phenytoin, levetiracetam, rufinamide, zonisamide, and lacosamide; 0.5-50 mg/L for lamotrigine, primidone, carbamazepine and 10-monohydroxycarbazepine; 0.2-10 mg/L for carbamazepine metabolites: 10,11-trans-dihydroxy-10,11-dihydrocarbamazepine and carbamazepine-10,11-epoxide; 0.1-10 mg/L for oxcarbazepine; 2-100 mg/L for felbamate and 3-150 mg/L for ethosuximide. The suitability of the validated method for routine therapeutic drug monitoring was confirmed by quantification of the analytes in plasma samples from patients with epilepsy on combination antiepileptic therapy.

Synthesis of Molecularly Imprinted Polymers Based on a New Monomer "2-(4-Vinylphenyl) Quinoline-4-Carboxylic Acid" for the Selective Solid-Phase Extraction of Lamotrigine

A new molecularly imprinted polymers (MIPs) have been prepared for the high selective extraction of lamotrigine (LTG), a widely used antiepileptic drug, in human serum. The MIPs were polymerized by bulk polymerization using our synthesized compound, 2-(4-vinylphenyl) quinolin-4-carboxylic acid, as functional monomer, which achieved better adsorption specificity than universal MIPs. Then, the molecularly imprinted solid phase extraction (MISPE) based on this material was coupled with high-performance liquid chromatography (HPLC) for the detection of LTG in human serum. The results of method validation showed that the developed method presented a good precision and accuracy, and the linearity was in the range of 1.50-40.00 mg/mL with the limit of quantitation (LOQ) at 0.20 mg/mL. The recovery ranged from 80.8% to 83.8% with RSD ranges from 5.5% to 11.1%. The validated method was successfully used to determine the concentration of LTG in human simulate serum samples.

A bibliometric analysis of the recent advances in diazepam from 2012 to 2021

Background: Diazepam is a classic benzodiazepine drug that has been widely used for disorders such as anxiety, sleep disorders, and epilepsy, over the past 59 years. The study of diazepam has always been an important research topic. However, there are few bibliometric analyses or systematic studies in this field. This study undertook bibliometric and visual analysis to ascertain the current status of diazepam research, and to identify research hotspots and trends in the past 10 years, to better understand future developments in basic and clinical research. Methods: Articles and reviews of diazepam were retrieved from the Web of Science core collection. Using CiteSpace, VOSviewer, and Scimago Graphica software, countries, institutions, authors, journals, references, and keywords in the field were visually analyzed. Results: A total of 3,870 publications were included. Diazepam-related literature had high volumes of publications and citations. The majority of publications were from the USA and China. The highest number of publications and co-citations, among the authors, was by James M Cook. Epilepsia and the Latin American Journal of Pharmacy were the journals with the most publications on diazepam and Epilepsia was the most frequently cited journal. Through a comprehensive analysis of keywords and references, we found that current research on diazepam has focused on its mechanism of action, application in disease, pharmacokinetics, risk, assessment, and management of use, status epilepticus, gamma-aminobutyric acid receptors (GABAR), intranasal formulation, gephyrin, and that ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) is the current research hotspot. Conclusion: Research on diazepam is flourishing. We identified research hotspots and trends in diazepam research using bibliometric and visual analytic methods. The clinical applications, mechanisms of action, pharmacokinetics, and assessment and management of the use of diazepam are the focus of current research and the development trend of future research.

Simultaneous determination of eight antiepileptic drugs and two metabolites in human plasma by liquid chromatography/tandem mass spectrometry

Epilepsy is one of the most prevalent neurological conditions and antiepileptic drugs are the mainstay of epilepsy treatment. High variation in pharmacokinetic profiles of several antiepileptic drugs highlights the importance of therapeutic drug monitoring to estimate pharmacokinetic properties and consequently individualize drug posology. In this work, a simple, rapid and robust liquid chromatography-tandem mass spectrometry method was developed for simultaneous quantification of carbamazepine and its metabolite carbamazepine-10,11-epoxide, gabapentin, levetiracetam, lamotrigine, oxcarbazepine and its metabolite mono-hydroxy-derivative metabolite, phenytoin, topiramate, and valproic acid in human plasma for therapeutic drug monitoring. d 6 -Levetiracetam, d 4 -gabapentin and d 6 -valproic acid were used as internal standards. After addition of internal standards along with two-step protein precipitation and dilution sample preparation, plasma samples were analyzed on a C18 column using a gradient elution in 5 min without interference. The calibration curves were linear over a 100-fold concentration range, with determination coefficients (r 2 ) greater than 0.99 for all analytes. The limit of quantification was 0.5 μg mL−1 (0.1 μg mL−1 for oxcarbazepine, 2 μg mL−1 for levetiracetam, and 10 μg mL−1 for valproic acid) with precision and accuracy ranging from 3% to 9% and from 94% to 112%, respectively. Intra- and inter-day precision and accuracy values were within 15% at low, medium and high quality control levels. No significant matrix effect was observed in the normal, hemolyzed, lipemic, and hyperbilirubin blood samples. This method was successfully used in the identification and quantitation of antiepileptic drugs in patients undergoing mono- or polytherapy for epilepsy.