Determination of vincristine in infant plasma by liquid chromatography-atmospheric pressure chemical ionization-mass spectroscopy.

An LC-MS method using APCI has been developed and validated for the determination of the anticancer drug vincristine in human plasma, using vinblastine as internal standard. Following solid-phase extraction (SPE) of the sample, the lower limit of quantitation (LLOQ) was 0.18 ng/ml, the lower limit of detection was 0.09 ng/ml, and the linear calibration range was 0.18-180 ng/ml. This method has been used to measure plasma concentrations of vincristine from 0.08 to 24 h post bolus in 29 infants as part of a pharmacokinetic study. Concentrations of vincristine at 24 h were 0.2-1.36 ng/ml.