Determination of lamotrigine in human plasma using liquid chromatography-tandem mass spectrometry

Determination of Antiepileptics in Biological Samples-A Review

Epilepsy remains a disease that affects many people around the world. With the development of new drugs to treat this condition, the importance of therapeutic drug monitoring continues to rise and remains a challenge for the medical community. This review article explores recent advances in the detection of antiepileptic drugs across various sample types commonly used for drug monitoring, with a focus on their applications and impact. Some of these new methods have proven to be simpler, greener, and faster, making them easier to apply in the context of therapeutic drug monitoring. Additionally, besides the classic use of blood and its derivatives, there has been significant research into the application of alternative matrices due to their ease of sample collection and capacity to reflect drug behavior in blood. These advances have contributed to increasing the efficacy of therapeutic drug monitoring while enhancing its accessibility to the population.

Determination of lamotrigine in human plasma by HPLC-PDA. Application to forensic samples

PURPOSE

Therapeutic drug monitoring of plasma lamotrigine (LTG) has customarily been carried out in order to prevent some its adverse effects. For forensic purposes, determination of LTG in plasma is an useful tool in cases of accidental overdose or suicidal attempts. Currently, there are several analytical methods available including some based on LC tandem mass spectrometry techniques, but simple and accessible LC-UV methods still can be useful for the purpose. Here we report on a new high-performance liquid chromatography method for the determination of lamotrigine in human plasma which has been developed and validated including selectivity, sensitivity, accuracy, precision and recovery studies.

METHODS

Lamotrigine and the internal standard chloramphenicol were extracted from plasma using liquid-liquid extraction using small volumes of buffer and ethylacetate. Detection was monitored at 305.7 and 276.0 nm for lamotrigine and chloramphenicol, respectively.

RESULTS

The method was linear concentration dependence within the range of 0.1-10 µg/ml, with a mean coefficient of correlation r = 0.993. The limit of detection (LOD) was 0.04 µg/ml and the limit of quantification (LOQ) was 0.1 µg/ml. Intra and interday precision values were lower than 9.0% at all concentrations studied. The intra and interday accuracy values ranged from - 7.6 to 10.1%. Recovery was found to be 98.9% or higher. The method here described was successfully applied to 11 postmortem blood samples received at the Forensic Sciences Institute of Santiago de Compostela (Spain).

CONCLUSION

A new HPLC method for the determination of lamotrigine in human plasma was developed and validated. A liquid-liquid extraction using small volumes of buffer and ethylacetate was optimized. The proposed method is suitable for forensic toxicological analysis.

Analysis of free concentrations of lamotrigine and active oxcarbazepine metabolite in clinical patients by hollow-fiber centrifugal ultrafiltration

Aim: To establish a simple and accurate method to explore the correlation between free and total concentrations of lamotrigine (LTG) and the active oxcarbazepine metabolite monohydroxy derivative (MHD) (10,11-dihydro-10-hydroxycarbamazepine) in clinical patients. Materials & methods: Serum samples were prepared by hollow-fiber centrifugal ultrafiltration and then injected into UPLC for analysis. Results: Absolute recovery was as high as approximately 90.1-98.6% with excellent precision (relative standard deviation <6.7%). Analysis time was reduced to 5 min. There were significant individual differences in the protein binding rates of both LTG and MHD that were probably due to the use of different clinical patients. Conclusion: Free concentrations of LTG and MHD cannot be estimated by total concentration in specific clinical patients. Free drug monitoring of LTG and MHD in clinical therapeutic drug monitoring is important and essential.

Comparison of HPLC-DAD and UPLC-MS/MS in Monitoring Serum Concentration of Lamotrigine

Background:

Lamotrigine (LTG) is a broad-spectrum and first-line anti-epileptic drug. To monitor the serum levels of LTG in epileptic seizures patients, high-performance liquid chromatography with diode-array detection (HPLC-DAD) and ultra-performance liquid chromatography-- tandem mass spectrometry (UPLC-MS/MS) methods were established and compared.

Methods:

Imatinib was used as the internal standard (IS) for both methods. LTG and IS were detected at 246 nm by HPLC-DAD. In UPLC-MS/MS, LTG and IS positive ion were detected by multiple reaction monitoring (MRM), with m/z of 256/210.9 and 494/394.02, respectively. A total of 37 blood samples from epileptic patients were determined and studied by these two methods.

Results:

There was an acceptable linearity for the two methods. The concentration range of LTG was 0.59 ~ 22.20 mg/L by HPLC, and 0.28 ~ 23.97 mg/L by UPLC-MS/MS. The Pearson regression coefficient of Deming regression was 0.9653 (95% CI: 0.9332 to 0.9821). Bland–Altman method demonstrated that the concentration of LTG determined by UPLC-MS/MS was 8.3% higher than that determined by HPLC (limits of agreement, -32.0% to +48.6%).

Conclusion:

There was a significant correlation between the two methods. Both HPLC and UPLC- MS/MS can be used for routine clinical monitoring of LTG.

Lamotrigine-A Review of Analytical Methods Developed for Pharmaceutical Formulations and Biological Matrices

Lamotrigine owing to its excellent inhibitory property of neurotransmitter release especially glutamate is used in the treatment of epilepsy as a second-line antiepileptic drug. It differs from other antiepileptic drugs chemically and pharmacologically and is used as both monotherapy and adjunct therapy in the treatment of epilepsy. The present review focuses on two aspects (a) various analytical methods used in quantification of Lamotrigine in pharmaceutical formulations and (b) various analytical methods used to determine Lamotrigine in biological matrices. Here the various analytical methods are developed using different parameters and validation of employed methods is discussed. Estimated parameters like the linearity, LOD (Limit of detection) and LOQ (Limit of quantification) of validation are discussed for the individual method. The critical quality attributes like the wavelength of detection, mobile phase, columns, flow rate, retention time, and the sample preparation methods for the estimation of Lamotrigine by bioanalytical methods are also discussed.

Determination of lamotrigine in human plasma using liquid chromatography-tandem mass spectrometry

Aim

Lamotrigine (LTG) is a widely used anti‐epileptic drug that is administered to avoid seizures and to maintain seizure‐free status. However, several factors reportedly cause individual differences of plasma LTG levels, and the therapeutic target range of LTG varies between individuals. Thus, to optimize effective doses of LTG, we developed a rapid and simple method for determining plasma LTG concentrations.

Methods

Lamotrigine and the internal standard papaverine were extracted from human plasma using solid‐phase extraction. After filtration, 5‐μL aliquots of final samples were injected into the liquid chromatography‐tandem mass spectrometry instrument and LTG and internal standard were separated using a Cadenza CD‐C18 column (100 × 2 mm, 3 μm) with 0.1% formic acid in water/acetonitrile (2/1, v/v).

Results

The calibration curve was linear from 0.2 to 5.0 μg/mL, and assessments of recovery, intra‐ and inter‐day precision and accuracy, matrix effects, freeze and thaw stability, and long‐term stability demonstrated good reproducibility. Retention times of LTG and internal standard were 1.6 and 2.0 minutes, respectively, and the total run time was 3.5 minutes for each sample.

Conclusion

We developed a rapid and simple method for determining plasma LTG concentrations. The present novel system could be used to inform LTG dose adjustments for individual patients.

We developed a rapid and simple method for determining plasma concentrations of LTG showing good validation for a relatively wide range (0.2‐5.0 μg/mL). The present method can inform estimates of plasma concentrations of LTG to clinicians within 1 hour of sample collection.