Optimized method for determination of gabapentin in serum by high-performance liquid chromatography.
The anticonvulsant drug gabapentin and its heptaneacetic acid analog-used here as an internal standard--are isolated from serum (pH 9) with an octyldecyl (C-18) solid-phase sorbent column. To enhance analytical detection, trinitrobenzene derivatives of these extracted compounds are prepared quickly within 10 min. To further improve chromatographic selectivity, the derivatives are concentrated on a thin C-18 solid-phase membrane and interferences are washed away. The retained purified derivatives are eluted from the membrane with a small volume of solvent and the eluate is directly injected onto an Ultrasphere C-18 high-performance liquid chromatography column with quantification at 340 nm. No evaporation-concentration steps are necessary. Recoveries (extraction) of gabapentin and the internal standard are 94.2 +/- 2.9% and 98 +/- 2.0%, respectively. Analytical responses are linear from lower limit of sensitivity of 0.05 mg/L up to at least 10 mg/L. Between-run coefficients of variation (CV) range from 2.3 to 2.9% through the concentration range 0.5-4.0 mg/L. To illustrate the rationale for selection of test parameters for a robust method, we present optimization graphs for these processes. Moreover, we discuss the advantage of the packed cartridge and membrane sorbens as companion extraction devices.
Lensmeyer
G L
GL
Department of Pathology, School of Pharmacy, University of Wisconsin Hospital and Clinics, Madison 53792, USA.
Kempf
T
T
Gidal
B E
BE
Wiebe
D A
DA
D000085:Acetates / Q000097:blood*; D000588:Amines; D000927:Anticonvulsants / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D003509:Cyclohexanecarboxylic Acids; D000077206:Gabapentin; D006801:Humans; D006863:Hydrogen-Ion Concentration; D005680:gamma-Aminobutyric Acid
D000085:Acetates; D000588:Amines; D000927:Anticonvulsants; D003509:Cyclohexanecarboxylic Acids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin