Aminopyridines 1 Antineoplastic Agents 1 Article 1 Benzimidazoles 1 Chromatography, High Pressure Liquid 1 Humans 1 Molecular Structure 1 abemaciclib 1 aminopyridine derivative 1 analytic method 1 antineoplastic agent 1 benzimidazole derivative 1 bioanalysis 1 chemical structure 1 clinical sample analysis 1 combination drugs controlled study 1 drug isolation 1 drug metabolite 1 drug stability 1 drug structure 1 first in human study 1 fit-for-purpose 1 hemolysis 1 high performance liquid chromatography 1 human 1 in vitro study 1 in vivo study 1 incurred sample reanalysis 1 limit of quantitation 1