Drug Monitoring by Volumetric Absorptive Microsampling: Method Development Considerations to Mitigate Hematocrit Effects

AIM: GSKA is a compound that was in development in clinical trials. A bioanalysis method to quantify GSKA using volumetric absorptive microsampling (VAMS) was developed and hematocrit (HCT) related assay bias was investigated. METHODOLOGY: After accurate sampling of 10 μl blood, VAMS tips were air dried approximately 18 h and desorbed by an aqueous solution containing internal standard. The recovered blood underwent liquid-liquid extraction in ethyl acetate to minimize matrix suppression. Assay accuracy, precision, linearity, carryover, selectivity, recovery, matrix effects, HCT effects and long-term quality control stability were evaluated. CONCLUSION: HCT-related assay bias was minimized in 30-60% blood HCT range, and all validation parameters met acceptance criteria. The method is suitable for quantitative analysis of GSKA in human blood.