At all times plasma levels of Ro 41-3290, the desethylated derivative of Ro 41-3696, are higher than those of the parent drug (t_max and t_1/2 values=~2 and 8 hours, respectively)^[1]. Pharmacokinetics of both Ro 41-3696 and its O-desethyl metabolite Ro 41-3290 are dose proportional and time independent. Ro 41-3696 is absorbed and eliminates rapidly (time of maximum plasma concentration, approximately 1 hour; elimination half-life, approximately 2 hours). Plasma levels of Ro 41-3290 are higher than those of the parent drug, and it is more slowly eliminated (values for time of maximum plasma concentration and elimination half-life, approximately 2 and approximately 7 hours, respectively)^[2].