Rapid and validated fluorometric HPLC method for determination of gabapentin in human plasma and urine for clinical application.

A rapid derivatization and validated HPLC method for gabapentin in human plasma and urine is needed for clinical use. The objective of this study was to establish a rapid and validated analytical method for the determination of gabapentin in human plasma and urine using isocratic fluorometric HPLC for clinical application. This analytical method is based on precolumn fluorescent derivatization using 4-fluoro-7-nitro-benzofurazan. The derivatization was coupled to fast HPLC separation using a 2·3 μm-particle size ODS column (100 × 4·6 mm i.d.). The derivatization of gabapentin was optimized and HPLC separation was achieved over an ODS column with a run time of 3·5 min. Calibration curves in human plasma and urine were linear over the concentration ranges of 0·05-10 and 10-1000 μg/mL, respectively. Intra- and inter-assay precision and accuracy values of plasma were within 8·0% and 101-109% and within 8·3% and 94-108%, respectively. Those of urine were within 8·5% and 97-106% and within 9·5% and 97-105%, respectively. This validated method was applied to a pharmacokinetic study in healthy subjects. Interindividual variations in plasma disposition and urinary excretion of gabapentin were observed. A rapid and validated isocratic fluorometric HPLC method for the determination of gabapentin in human plasma and urine for clinical application has been established. This method can be utilized to evaluate the pharmacokinetic disposition of gabapentin in humans.