Permeability of DNDI-VL-2098 (10 μM) was determined in apical to basolateral (A–B) and basolateral to apical (B–A) directions. Transport studies were conducted 21 days post seeding in 12-well Transwell® inserts. Following pre-incubation

in HBSS-HEPES buffer in an orbital shaker (37 °C, 5% CO2, 30 min), trans-epithelial electric resistance (TEER) values were measured and only those inserts with values above 300 Ω cm2 were considered for assay. HBSS-HEPES buffer was removed and DNDI-VL-2098 spiked HBSS-HEPES buffer (1% final DMSO concentration) buy PD0325901 was added to each donor compartment in triplicate. Blank HBSS-HEPES buffer containing 1% DMSO was added to the receiver compartment. Samples were withdrawn from the receiver chamber Erlotinib research buy at 30, 60, 90, and 120 min, and from the donor chamber at 0 and 120 min. TEER values were measured after completion of assay to ensure monolayer integrity. At the end of the experiment, cells were washed with cold buffer and lysed with acetonitrile to assess cell accumulation and estimate the recovery. Apparent permeability (Papp), efflux ratio (Papp(B–A)/Papp(A–B)), cell accumulation (concentration in buffer and acetonitrile wash) and recovery (total amount recovered/initial amount added) were calculated. Rhodamine-123 (substrate for P-gp) was run as positive control. Microsomes from males of golden Syrian hamster, CD-1 mouse, Sprague–Dawley

rat, and Beagle dog, and mixed gender human (pool of 50) were used for assays. Ribonucleotide reductase Incubations (1 mL) consisted of liver microsomes (0.5 mg/mL), NADPH (2 mM) and 50 mM phosphate buffer (pH 7.4). Following pre-incubation (10 min, 37 °C), reactions were initiated by adding DNDI-VL-2098 (0.5 μM). Samples (50 μL) were withdrawn at 0, 3, 6, 9, 12, 15, 18, 21, 27 and 30 min and quenched

with 50 μL acetonitrile containing internal standard. Concomitant NADPH-free control incubations were made similarly with samples collected at 0 and 30 min. Verapamil (hamster, mouse and dog liver microsomes) and diclofenac (rat and human liver microsomes) were concomitantly used as positive control substrates. Hepatocyte suspensions (CD-1 mouse, Wistar rat, Beagle dog, human; male) containing 106 cells/mL were used for the incubations. Following pre-incubation of cell suspension (995 μL, 10 min, 37 °C, 5% CO2), reactions were initiated by addition of 5 μL DNDI-VL-2098 stock solution (final concentration in assay was 0.5 μM). Samples (100 μL) were taken at 0, 5, 15, 30, 60, and 90 min, and quenched with 100 μL acetonitrile. Hepatocyte-free control incubations were prepared by spiking 5 μL of DNDI-VL-2098 into 995 μL of Waymouth’s media, and aliquots (100 μL) were taken at 0 and 90 min. A cocktail mixture containing phenacetin, diclofenac, 7-hydroxycoumain, bufuralol and midazolam was concomitantly used as positive control substrates.