PNU-103017 is a racemic mixture of two enantiomers, designated PNU-103264 (R-) and PNU-103265 (S-). PNU-103017 is a selective HIV aspartyl protease inhibitor under evaluation as a potential oral treatment of Acquired Immunodeficiency Diseases. The Cmax (P≤0.0349), Cmin (P≤0.0168), and Cav (P≤0.0118) are significantly higher for the (R)- than the (S)-enantiomer, displaying enantioselective pharmacokinetics of PNU-103017 in the dog[1].