In vitro plasma stability study

Male ICR mice of 6-week-old were sacrificed, and the mouse blood samples were collected via cardiac puncture into EDTA tubes placed on ice. Plasma samples were obtained by centrifugation (3000 rpm for 15 min at 4 °C) and kept frozen at −20 °C until use. The plasma was subjected to in vitro compound stability study. The plasma aliquots of 70 μL were distributed to 0.6 mL microcentrifuge tubes (Basic Life, Taipei, Taiwan). BPRDP056 was dissolved in a mixture of DMSO and D5W (1:9, v/v) and 70 μL of the mixture each was added into the plasma tubes, followed by a 3-, 6- and 24-h incubation (n = 3 for each incubation time) at 37 °C in a water bath. The samples were measured for levels of BPRDP056 and SN38 released from cleavage of BPRDP056 by HPLC analysis.