Characterization and application of restricted access carbon nanotubes in online extraction of anticonvulsant drugs from plasma samples followed by liquid chromatography analysis

- Restricted access carbon nanotubes (RACNTs) were synthesized.
- The RACNTs were unprecedently used to analyze anticonvulsants in plasma samples.
- The RACNTs promoted the exclusion of proteins and other concomitants from plasma.
- The developed method exhibited suitable validation parameters.
- The method is simple, quick, cheap and followed the principles of green chemistry.

Anticonvulsant drugs are often used in the treatment of epilepsy. However, their therapeutic monitoring is often necessary in order to obtain an appropriate dose adjustment, due to the proximity between their therapeutic and toxic ranges. The aim of this study was to carry out the synthesis, characterization and use of restricted access carbon nanotubes (RACNTs) in an online method for the analyses of phenobarbital and carbamazepine and primidone from untreated human blood plasma by column switching liquid chromatography. Therefore, the synthesis of RACNTs was carried out through coating commercial Carbon nanotubes with bovine serum albumin (BSA) to subsequently use them as adsorbents in a column switching system operating in the backflush mode. This material was evaluated through the construction of the kinetic and isotherm curves. The experimental data for the interaction of primidone with RACNTs were adequately adjusted to the chemisorption and Sips models for the kinetic and adsorption studies, respectively. The analytical curves ranged from 2.0 to 40.0 mg L−1, with correlation coefficients higher than 0.99, for all the analytes. The LODs of 0.1, 0.1 and 0.01 μg mL−1 were defined for PHB, PRM and CBZ, respectively. The relative standard deviation values ranged from 1.0% to 8.4% for the intra assay precision and from 2.7% to 7.6% for inter assay precision. The relative error values ranged from −13.4% to 7.7% for the intra assay accuracy and from −8.6% to 2.5% for the inter assay accuracy. The method was adequately used in the therapeutic monitoring of anticonvulsant drugs in human plasma samples.