Development and validation of a new HPlc method for determination of lamotrigine and clinical application

Abstract

SUMMARY
Background: Lamotrigine is an effective anticonvulsant drug used in the treatment of epilepsy. It has a narrow therapeutic range, a large inter and intra-individual pharmacokinetic variability and some concentration-dependent side effects.
Aim: The aim of this study was to develop and validate a new method for lamotrigine quantitation in plasma using HPLC with UV/visible detection.
Methods: A rapid HPLC-UV method was developed for the determination of lamotrigine in plasma. All solvents used were HPLC grade.
Results: After liquid-liquid extraction, chromatographic separation was achieved using an RP 18 (250 mm) column. The mobile phase was composed of acetonitrile and 0.1 M potassium dihyrogenophosphate (25/75) (v/v). Barbital sodium was used as internal standard. This technique was linear over the 2 μg/mL to 50 μg/mL range (r= 0.99). Detection and quantification limits were 0.07 μg/mL and 0.21 μg/mL, respectively. Within-day coefficient of variation (13.37 to 16 %) and day-to-day coefficients of variation (15.68 to 16.63 %) at three different concentrations. Under these conditions, each analysis required no longer than 10 min. We finally evaluated the plasma concentrations of lamotrigine in Tunisian patients treated with this drug.
Conclusion: The results found are similar to those previously described and the developed method is repeatable and reproducible. It can be used for clinical applications.