Development and Validation of a Stability-indicating Liquid Chromatography-Tandem Mass Spectrometry Method for Simultaneous Quantification of Pazopanib and Gemcitabine in Plasma: Overcoming Polarity and Stability Challenges

Abstract

Background: Objectives Pazopanib and Gemcitabine are valuable anticancer drugs; when co-administered can be very difficult to quantitate from plasma due to differences in their polarities coupled with the inherent instability of Gemcitabine, and this necessitates a highly sensitive and robust method for simultaneous determination. Aim: This study developed and validated a liquid chromatography-tandem mass spectrometry (LC–MS/MS) method for simultaneous determination of Pazopanib and Gemcitabine in plasma that was stability-indicating, which considers polarity, matrix effects, and instability of Gemcitabine. Methods: The method was a gradient LC–MS/MS performed on a C18 column, with chilling the extraction solvent to −80°C before adding acetonitrile
and using Zebularine for molecular stabilization, validated according to the International Council for Harmonisation (ICH) M10 and Food and Drug Administration (FDA) criteria. Results: The method displayed superb selectivity, sensitivity, linearity, reproducible recovery variability (RSD <0.09), as well as correlations of matrix effects with bias in the spiked samples; however, the stability was within standard limits, and accuracy/precision values were acceptable as well. Discussion: This method not only solved the issues of polarity and stability, but also gave reproducibility to pharmacokinetic use. Conclusion: The developed and validated LC–MS/MS method provides a simple, selective, sensitive, and stability-indicating solution to the simultaneous analysis of Pazopanib and
Gemcitabine in plasma samples.