Microdosing Clinical Study: Pharmacokinetic, Pharmacogenomic (SLCO2B1), and Interaction (Grapefruit Juice) Profiles of Celiprolol Following the Oral Microdose and Therapeutic Dose
The Journal of Clinical Pharmacology May 19, 2011 Ichiro Ieiri, Yohei Doi, Kazuya Maeda et al. 106 citations
In 30 healthy volunteers matched for SLCO2B1 genotype, the effect of a genetic variant on the body's exposure to celiprolol depended on the dose. At a therapeutic dose (100 mg), people with two copies of the *3 variant had a lower average area under the concentration-time curve (AUC) of 775 ng·h/mL compared with 1097 ng·h/mL for those with one copy (*1/*3) and 1547 ng·h/mL for those with none (*1/*1). At a microdose (97.5 µg), these genotype differences disappeared. Dose-normalized AUC was much lower at the microdose, suggesting saturation of an efflux transporter at the therapeutic dose explains why the genetic effect only appears at that higher dose.