Development and Validation of a Standardized Workflow for Multi-Species Liver Microsome Preparation

Abstract Liver microsomes are widely used to assess metabolic stability and intrinsic clearance, yet substantial variation exists in laboratory preparation protocols, and the detailed manufacturing processes of commercial reference products are often undisclosed, together limiting methodological transparency and cross-study reproducibility. Metabolic stability was assessed using testosterone, verapamil, raloxifene, and ketanserin. The CD-1 mouse and Sprague-Dawley rat microsomes were compared with the corresponding XenoTech reference microsomes. Beagle dog microsomes were evaluated using the same probe substrates, but no commercial beagle dog reference microsomes were included. The results provide a preliminary functional characterization of the workflow. For some probe substrates, the depletion profiles of the in-house mouse and rat preparations appeared broadly similar to those of their corresponding XenoTech reference microsomes. These descriptive observations do not establish equivalence or superiority. Reproducibility and suitability for routine application require further validation.