DPC-681 is a potent and selective HIV protease inhibitor with IC90 values ranging from 4 to 40 nM for wild-type HIV-1.

DPC 681 displays no loss in potency toward recombinant mutant HIVs with the D30N mutation and a fivefold or smaller loss in potency toward mutant variants with three to five amino acid substitutions. When all of the HIV-1 strains tested are considered, the average concentrations required for 90% inhibition of replication were 7.3 ± 3.4 for DPC 681.

The total body clearance (CL) of DPC 681 in dogs was high (1.8 liters/h/kg) equaling hepatic blood flow for this species (1.8 liters/h/kg). The Cmax increased ninefold between the 10- and 30-mg/kg DPC 681 dose groups. Bioavailability also increased between the 10- and 30-mg/kg dose groups (18.3 and 78.1%, respectively), after oral dosing. These data show that hepatic extraction (first-pass effect) can be saturated in the dog.