4.9. PAMPA Permeability Assay

Passive permeabilities of exatecan mesylate and DXd (both from MedChemExpress) were compared by parallel artificial membrane permeability assay (PAMPA assay) using a GenTest^TM pre-coated PAMPA plate system (Corning, New York, NY, USA, Cat#353015), following the manufacturer’s protocol and calculation procedures. The assay buffer was PBS (pH 7.4) + 10% MeOH (v/v). The initial compound concentration in the donor compartment was 100 µM. Residual DMSO in the assay was kept below 1% (v/v). The permeability partitioning was realized for 5 h at room temperature while stirring the plate at 300 rpm on a Heidolph Titramax 101 device. Final concentration of tested compound in the donor and acceptor compartments was assessed by HPLC–UV, against known calibration curves of compounds.