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

Abstract

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 Lichro-CART 250-4 ChiraDex (␤-cyclodextrin, 5 m) column at 30• C. The UV detector was set at 225 nm. Calibration curves were linear (r 2 ≥ 0.996) in the ranges 0.4-8 g mL −1 , 0.1-1.5 g mL −1 and 0.1-2 g mL −1 for ESL and OXC and in the ranges 0.4-80 g mL −1 , 0.1-15 g mL −1 and 0.1-20 g 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.

The role of carbonyl reducing enzymes in oxcarbazepine in vitro metabolism in man

“…Chiral separation of MHD enantiomers was performed on the LiChrocart Ò 250-4 Chiradex (5 lM) column (Merck, Darmstadt, Germany). The HPLC method was optimized with regard to previously published papers [15][16][17]. The mobile phase consisted of 10% methanol in water (v/v).…”

Evaluation of neurotoxic and neuroprotective pathways affected by antiepileptic drugs in cultured hippocampal neurons

“…ESL is structurally different at the 10,11-position, and consequently, it is not metabolized to CBZ-10,11-epoxide and, therefore, it is not susceptible to enzyme induction or autoinduction (Bialer, 2006). Moreover, ESL is a once-daily AED (Almeida and Soares-da-Silva, 2007) that is rapidly absorbed and undergoes extensive first-pass metabolism, in humans (Almeida et al, 2005) and mice (Alves et al, 2007), to its main active metabolite, eslicarbazepine (S-Lic), which is responsible for approximately 95% of total systemic drug exposure, and to a lesser extent to Rlicarbazepine (R-Lic) and OXC, (Almeida et al, 2005). Our group previously demonstrated that ESL is less toxic to cultured neurons than CBZ and OXC, namely at high concentrations (0.3 mM).…”

A chiral HPLC‐UV method for the quantification of dibenz[b,f]azepine‐5‐carboxamide derivatives in mouse plasma and brain tissue: Eslicarbazepine acetate, carbamazepine and main metabolites

“…Moreover, all the calibration standards were within the acceptance criteria defined by the guidelines (720% for LOQ standards and715% for non-LOQ standards) ( Table 1). It is important to state that the upper limit of quantification for OXC was enhanced in relation to previous works [27] allowing the application of the present method during pharmacokinetic studies in which OXC itself is administered to mouse. The LOQs of each analyte in both matrices are depicted in Table 1 as well as the corresponding validation parameters.…”

“…However, so far, there is no analytical technique published with those characteristics. In fact we have already published a method to quantify ESL, S-Lic, R-Lic and OXC in those biological matrices, but it was not developed nor validated for CBZ and CBZ-E [27]. Thus, we developed a sensitive, selective, precise and accurate chiral HPLC-UV method to quantify simultaneously ESL, CBZ, S-Lic, R-Lic, OXC and CBZ-E (Fig.…”