Simultaneous and enantioselective liquid chromatographic determination of eslicarbazepine acetate, S-licarbazepine, R-licarbazepine and oxcarbazepine in mouse tissue samples using ultraviolet detection Original Research Article

Herein is reported, for the first time, a simple and reliable chiral reversed-phase liquid chromatographic method coupled to ultraviolet (UV) detection for simultaneous determination of eslicarbazepine acetate (ESL) and its metabolites, S-licarbazepine (S-LC), R-licarbazepine (R-LC) and oxcarbazepine (OXC), in mouse plasma and brain, liver and kidney tissue homogenates. All analytes and the internal standard were extracted from plasma and tissue homogenates by a solid-phase extraction procedure using Waters Oasis® hydrophilic–lipophilic balance cartridges. The chromatographic separation was performed by isocratic elution with water/methanol (88:12, v/v), pumped at a flow rate of 0.7 mL min−1, on a LichroCART 250-4 ChiraDex (β-cyclodextrin, 5 μm) column at 30 °C. The UV detector was set at 225 nm. Calibration curves were linear (r2 ≥ 0.996) in the ranges 0.4–8 μg mL−1, 0.1–1.5 μg mL−1 and 0.1–2 μg mL−1 for ESL and OXC and in the ranges 0.4–80 μg mL−1, 0.1–15 μg mL−1 and 0.1–20 μg mL−1 for R-LC and S-LC in plasma, brain and liver/kidney homogenates, respectively. The overall precision not exceeded 11.6% (%CV) and the accuracy ranged from −3.79 to 3.84% (%bias), considering all analytes in all matrices. Hence, this method will be a useful tool to characterize the pharmacokinetic disposition of ESL in mice.