The use of a packed column for the determination of bupivacaine in human plasma by gas chromatography: an application in a pharmacokinetic study of bupivacaine.

The method involves a single extraction of the drug and the internal standard, etidocaine, from alkalinized plasma with n-hexane. The gas chromatograph is equipped with a glass column (2.0 m x 2 mm) packed with 3% W/W SP2250 on Chromosorb W, (80/100 mesh) and a nitrogen sensitive detector. The method can accurately measure plasma bupivacaine concentrations down to 0.01 micrograms ml-1 using a sample size of 0.5 ml. The day-to-day variation of bupivacaine at 2.0 micrograms ml-1 is 6.90% (n = 10). The calibration graph is linear over the range 0.1-4.0 micrograms ml-1. The method is accurate, fast and sensitive and has been applied in a pharmacokinetic study of bupivacaine.