Determination of lamotrigine in small volumes of plasma by high-performance liquid chromatography

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 817; no. 2; pp. 199 - 206
• Main Authors: CHENG, Ching-Ling, CHOU, Chen-Hsi, HU, Oliver Yoa-Pu
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science 25.03.2005
• Subjects: Analysis; Analytical, structural and metabolic biochemistry; Anticonvulsants - blood; Anticonvulsants - pharmacokinetics; Biological and medical sciences; Chromatography, High Pressure Liquid - methods; Fundamental and applied biological sciences. Psychology; General pharmacology; Humans; Medical sciences; Pharmacology. Drug treatments; Reproducibility of Results; Spectrophotometry, Ultraviolet; Triazines - blood; Triazines - pharmacokinetics; HPLC chromatography; Plasma volume; Anticonvulsant; Triazine derivatives; Quantitative analysis; Lamotrigine
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2004.12.004

Lamotrigine is a broad-spectrum antiepileptic agent. This study describes a simple and sensitive high-performance liquid chromatographic method for the determination of lamotrigine in 50 microl of plasma. Lamotrigine and the internal standard guanabenz were extracted with 1.2 ml of diethyl ether, after the samples alkalinized with 10 microl of sodium hydroxide solution (1N). Chromatographic separation was achieved on a silica column with the mobile phase of acetonitrile-water containing 0.2% phosphoric acid and 0.3% triethylamine (pH 2.7) (84:16, v/v), at a flow-rate of 1 ml/min. The eluant was detected at 225 nm. The retention time was about 6 min for lamotrigine and 7 min for guanabenz. No endogenous substances and concomitant anticonvulsants were found to interfere. Calibration curves were linear from 0.1 to 5 microg/ml. The relative recovery of lamotrigine averaged about 80%. The limit of quantitation was 0.1 microg/ml. The intra- and inter-day precision (expressed as coefficient of variation, CV) was 8.1%, or less, and the accuracy was within 11.5% deviation of the nominal concentration. The method is suitable in pharmacokinetic investigation and monitoring lamotrigine concentration.