[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.