Microporous polymer based on the new compound "bi-(4-vinyl phenylquinoline) amide" for enrichment and quantitative determination of lamotrigine in rat and human serum

Preparation of a β-cyclodextrin grafted magnetic biochar for efficient extraction of four antiepileptic drugs in plasma samples

Simultaneous monitoring of plasma concentration levels of multiple antiepileptic drugs (AEDs) is essential for dose adjustment in comprehensive epilepsy treatment, necessitating a sensitive technique for accurate extraction and determination of AEDs. Herein, a magnetic solid-phase extraction (MSPE) technique on the basis of modified biochar (BC) is investigated to extract four AEDs from plasma, in conjunction with high performance liquid chromatography. BC derived from Zizyphus jujuba seed shells was activated by phosphoric acid (PBC) and magnetized via coprecipitation to produce MPBC. The MPBCCD obtained after modification with β-cyclodextrin (CD) was characterized and evaluated for adsorption. It exhibited fast adsorption kinetics based on second-order kinetics and satisfactory adsorption capacity for AEDs. Then it was employed as the MSPE adsorbent and the influencing parameters were optimized. The enrichment factor was 18.75. The validation analysis revealed a favorable linearity that ranged from 0.04 to 20 μg·mL-1 along with a low limit of detection of 6.85 to 10.19 ng·mL-1. The recovery of the AEDs ranged from 78.7 to 109.2 %, with relative standard deviations below 6.7 %. Using quantum chemistry theory calculations and experimental results analysis, the adsorption mechanism was investigated. It disclosed that the suggested strategy built upon MPBCCD was appropriate for the assessment of AEDs in plasma and expanded the usage of BC as the environmentally favorable matrix for the analysis of biological samples.

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.

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.

Development of magnetic molecularly imprinted polymers with double templates for the rapid and selective determination of carbamazepine and lamotrigine in serum

A dual-template magnetic molecularly imprinted polymer (Dt-MMIP) with a specific recognition capability for carbamazepine (CBZ) and lamotrigine (LTG) was synthesized using methacrylic acid as a functional monomer, and ethylene glycol dimethylmethacrylate as a cross-linking agent. A magnetic non-molecularly imprinted polymer without templates (MNIP) was also prepared using the same procedure. The prepared polymers were characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy and adsorption experiments. Results indicated that both Dt-MMIPs and MNIPs were microspherical nanoparticles, and the surface of the Dt-MMIP was rougher than that of the MNIP. In addition, the prepared Dt-MMIPs possessed a higher adsorption capacity and better selectivity for CBZ and LTG than the MNIPs. The maximum static adsorption capacities of Dt-MMIP for CBZ and LTG were 249.5 and 647.9 μg g^-1, respectively, whereas those of MNIP were 75.8 and 379.8 μg g^-1, respectively. The obtained Dt-MMIPs were applied as a magnetic solid-phase extraction sorbent for the rapid and selective extraction of CBZ and LTG in rat serum samples, and determination was performed by high-performance liquid chromatography with UV detection (HPLC-UV). The developed method of dispersive SPE based on Dt-MMIPs coupled to HPLC-UV has good rapidity and selectivity, and application prospects in serum.

Spectrophotometric determination of lamotrigine in plasma samples: Ultrasound-assisted emulsification-microextraction based on a hydrophobic deep eutectic solvent followed by back-extraction

In this study, sensitive detection of lamotrigine in human plasma samples was realized at a low cost approach through ultrasound-assisted emulsification-microextraction based on using a hydrophobic deep eutectic solvent followed by back-extraction (USAEME-DES-BE) method. After extraction, detection and quantification of lamotrigine were done by spectrophotometry in the UV region. The hydrophobicity of the deep eutectic solvent not only eliminates the need of the third solvent as an emulsifying agent but also helps to retrieve lamotrigine from the DES by back-extraction to another aqueous phase. The back extraction process allowed the drug to be measured in the UV region. Central composite design in combination with a desirability function approach was applied for the optimization of the USAEME-DES-BE procedure. Essential factors in the method efficiency were discussed, such as back-extraction solution, time of back-extraction, the ratio of DES components, pH, the volume of DES, salt concentration, and sonication time. The method exhibited a wide dynamic linear range from 0.5 to 10 µg mL^-1 and a limit of detection of 0.15 μg mL^-1. The established method was successfully applied to determine lamotrigine in human plasma samples with satisfactory relative recoveries.