DETERMINATION OF BUPIVACAINE IN HUMAN PLASMA BY HPLC

A rapid, sensitive, selective and reproducible reversed- phase high-pe rformance liquid chromatographic method has been developed and validat ed for the quantification of bupivacaine in human. Bupivacaine and the internal standard, lidocaine, are extracted from alkalinized plasma u sing n-hexane before chromatographing on a reversed-phase system. The mobile phase comprises 62 parts of 0.05 M phosphate buffer and 38 part s of methanol at pH 5.9 and it is pumped at 1.0 ml/min. The retention times of bupivacaine and lidocaine were observed to be 3.8 and 5.9 min respectively. Ultraviolet detection at 254 nm enabled a limit of dete ction of 25 ng/ml to be achieved. The reproducibility of the method wa s good at 1000 ng/ml (C.V.=4.3%, n=6). The method is linear from 50 to 3200 ng/ml. The high sensitivity and the speed at which this assay ca n be performed makes it especially useful for estimating bupivacaine i n human plasma.