The pharmacokinetic behavior of the glucosidase inhibitor and antiviral compound JV-benzyl-1-deoxynojirimycin (BndNM) was studied in rats in vivo and in isolated perfused livers. BndNM is a more lipophilic derivative of the glucosidase inhibitor A'-methyl-1-deoxynojirimycin (MedNM). This was reflected in the n-octanol/Krebs partition coefficients, which were 0.28 and 0.004, respectively. Compared with previously published data on the N-methyl analog, derivatization with the benzyl moiety caused an increase in both elimination half-life (from 32 min for MedNM to 69 min for BndNM) and steady-state distribution volume (164 mL for MedNM and 322 mL for BndNM) in vivo. The fraction of the dose excreted in urine after 2 h was decreased (66% for BndNM compared to 80% for MedNM), the fraction excreted in bile after 2 h was increased, both in vivo (1.5% of BndNM compared to 0.2% for MedNM) and in perfused livers (5% for BndNM compared to 0.5% for MedNM). Clearance decreased from 6.3 (MedNM) to 4.0 mL/min (BndNM). In unanesthetized rats, bioavailability of BndNM was found to be 100% after oral dosing. Fractionation of liver homogenates showed that BndNM was mainly present in the cytosolic fraction, with a slight accumulation in the lysosomal/endosomal fraction. The authors conclude that addition of the lipophilic phenyl group to the deoxynojirimycin backbone leads to more favorable pharmacokinetic properties of the glucosidase inhibitor.