Lidocaine was one of the first in class amino-amide type local anesthetics. Lidocaine is commonly used to relieve skin irritations and injected during dental and minor surgeries. As lidocaine formulations and delivery techniques are improved, the need to measure systemic levels of lidocaine in plasma is warranted.

Previous HPLC or LC/MS/MS assays required run times >10 minutes and/or laborious extraction procedures for the analysis of lidocaine from biological fluids.1 Here we report on a simple preparation method coupled with LC/MS/MS to provide an accurate and precise assay with a 5 minute run time for the determination of lidocaine from rat and mini-pig plasma.