title: Analysis of lamotrigine and lamotrigine 2-N-glucuronide in guinea pig blood and urine by reserved-phase ion-pairing liquid chromatography.
abstract: Lamotrigine is an investigational anticonsulvant drug undergoing clinical trials. A simultaneous assay was developed to quantitate lamotrigine and its major metabolite, lamotrigine 2-N-glucuronide, from guinea pig whole blood. The extraction procedure and reversed-phase high-performance liquid chromatographic (HPLC) assay employed sodium dodecylsulfate (SDS) as an ion-pairing reagent to selectively separate lamotrigine and lamotrigine 2-N-glucuronide from endogenous blood components, other anti-convulsant drugs, and their metabolites. The mobile phase was composed of acetonitrile-50 mM phosphoric acid (pH 2.2) containing 10 mM SDS (33:67, v/v), and components were detected at 277 nm. The total coefficients of variance (C.V.) for the blood assay were less than or equal to 9.4% for lamotrigine (0.25-20.0 micrograms/ml) and less than or equal to 13.4% for the glucuronide metabolite (0.25-10.0 micrograms/ml). Separate assays for lamotrigine and its glucuronide in urine were developed. In order to quantitate low levels of lamotrigine in guinea pig urine, lamotrigine was extracted with tert.-butyl methyl ether-ethyl acetate (1:1). The total C.V. for lamotrigine quantitation in urine was less than or equal to 7.5% (0.10-10.0 micrograms/ml). For the determination of lamotrigine 2-N-glucuronide, urine was diluted with an SDS-phosphoric acid buffer (1:4) and injected directly onto the HPLC system, total C.V. less than or equal to 4.2% (0.5-50 micrograms/ml).
authors.affiliation: Department of Medicinal Chemistry, University of Minnesota, Minneapolis 55455.
authors.forename: M W
authors.initials: MW
authors.lastname: Sinz
authors.forename: R P
authors.initials: RP
authors.lastname: Remmel
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000097:blood* / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006168:Guinea Pigs; D000077213:Lamotrigine; D008297:Male; D014227:Triazines / Q000097:blood* / Q000652:urine*
chemical_list: D000927:Anticonvulsants; D014227:Triazines; C074259:lamotrigine 2-N-glucuronide; D000077213:Lamotrigine