Discovery pharmacokinetic studies in mice using serial microsampling, dried blood spots and microbore LC-MS/MS

Initial pharmacokinetic (PK) studies of discovery compounds are conducted in mice to demonstrate exposure prior to conducting efficacy studies. PK information obtained from a single mouse by serial blood microsampling, dried blood spot collection and analyses using microbore (1 mm internal diameter column) LC-MS/MS is presented. Ex vivo blood to plasma concentration ratios (BPRs) from mouse PK studies were compared with in vitro BPRs for 15 compounds.

Two compounds were orally dosed and blood was collected at time points via serial blood sampling. The calculated PK parameters (AUC, T(max) and C(max)) were comparable across liquid blood, dried blood spot and plasma matrices. The BPR results from both methods were comparable.

Serial blood microsampling has led to reduced animal and compound usage with improved PK data. Ex vivo BPR is suitable in a discovery setting. Microbore LC-MS/MS is well suited in instances where sample volume is limited, and enables faster analyses, reduced solvent use, and less frequent MS source cleaning.