Population pharmacokinetic-pharmacodynamic modeling of TF-505 using extension of indirect response model by incorporating a circadian rhythm in healthy volunteers.
The pharmacokinetic-pharmacodynamic (PK-PD) relationship of the newly developed drug, (-)-(S)-4-[1-[4-[1-(4-isobutylphenyl)butoxy]benzoyl]indolizin-3-yl]butyric acid (TF-505), was characterized via a population approach in early human study. Healthy volunteers were divided into six groups. The groups received four single doses (25, 50, 75 or 100 mg) and 2 multiple doses (12.5 or 25 mg) of TF-505, respectively. Dihydrotestosterone (DHT) data were collected to assess TF-505 pharmacodynamics. Population PK/PD modeling of TF-505 was performed via mixed-effects modeling using the NONMEM software package. The final PK-PD model incorporates a two-compartment PK model and an extended indirect PD model. The population PK parameters were 0.197 h(-1) for the k(a), 0.0678 h(-1) for k(e), 12.5 l for V(c), 0.0645 h(-1) for k(12), 0.0723 h(-1) for k(21). Extension of indirect response model by incorporating a time-dependent periodic function for k(in) takes into account the chronopharmacologic rhythms (I(max): 0.706+/-0.297, IC(50): 1.01+/-1.64 (microg/ml), k(out): 0.221+/-0.0486 (h(-1)), R(m): 20.4+/-8.08 (% h(-1)), R(amp): 5.06+/-3.43 (% h(-1)), T(z): 5.01+/-0.407 (h) (Population mean+/-S.E.)). R(m) is the mean DHT synthesis rate, R(amp) is the amplitude of the DHT synthesis rate, and T(z) is the acrophase time, signifying maximum synthesis rate. The present study represents a successful population PK-PD model using the full data from early human studies. The population parameters thus obtained could provide useful indicators for the determination of dosage regimens in exploratory studies in patient populations.
Matsumoto
Yoshiaki
Y
Department of Clinical Pharmacology and Toxicology, Showa Pharmaceutical University, 3-3165 Higashitamagawagakuen, Machida, Tokyo 194-8543, Japan. matsuy@pha.nihon-u.ac.jp
Fujita
Tomoe
T
Ishida
Yoshimasa
Y
Shimizu
Makiko
M
Kakuo
Hiroyuki
H
Yamashita
Kazumasa
K
Majima
Masataka
M
Kumagai
Yuji
Y
D000328:Adult; D002940:Circadian Rhythm; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007212:Indolizines / Q000493:pharmacokinetics* / Q000494:pharmacology*; D008297:Male; D008954:Models, Biological; D011159:Population Surveillance
C106324:FR 146687; D007212:Indolizines