[Decomposition kinetics of bupivacaine in biological specimens].

Objective: To study on the decomposition kinetics of bupivacaine in brain, blood and urine, which were collected from dogs executed by bupivacaine and stored in different conditions.
Methods: Dogs were given arachnoid cavity anesthesia with bupivacaine. Then the brain, blood and urine were collected and divided equally to three groups stored in 20, 4 and -20 degrees C respectively. The concentrations of bupivacaine at different days were determined by the GC. The equation and half-time period of decomposition kinetics were imitated and calculated with WinNolin program.
Results: The decomposition kinetics of bupivacaine in the dogs' brain, blood and urine were fit to the first order kinetics. The common equation was lgC = lgCo-kt/2.303 and k was the decomposition constant of first order reaction.
Conclusion: Bupivacaine in the brain, blood and urine specimens were found to be decomposed at various environments for storage. The higher temperature for storage, the faster of decomposition reaction.