Quantitative Analysis Of Pilocarpine In Human Plasma Using LC-MS/MS

By Iris Stadelmann and William Sawyers

Pilocarpine belongs to a class of medications known as cholinergic parasympathomimetics and is a naturally occurring alkaloid in the leaves of South American shrub Pilocarpus jaborandi.

Sample cleanup was accomplished using an automated liquid-liquid extraction of 0.2 mL aliquots of human plasma. An isocratic HPLC method (5-6 minutes run time, 0.25-0.50 mL/min flow rate, acetonitrile:buffered aqueous mobile phase) was used. A structural analogue of pilocarpine was selected as the internal standard. A Micromass Quattro tandem mass spectrometer was operated in the positive ion mode via electrospray. Data was collected using multiple reaction monitoring.

To ensure specificity of the extraction procedure, six lots of plasma were tested. Aliquots of each plasma lot containing 20.0 ng/mL of pilocarpine were extracted and analyzed. The coefficient of variation was 9.21% and the accuracy was 102.00% for pilocarpine.