Table 3.
Estimated population pharmacokinetic parameters for the gonadotropin-releasing hormone (GnRH) agonist triptorelin and the GnRH receptor blocker degarelix
| Population mean | IIV | ||||
|---|---|---|---|---|---|
| Parameter | Unit | Estimate | (RSE, %) | CV (%) | (RSE, %) |
| Triptorelin pharmacokinetic parameters | |||||
| t1/2,im | (days) | 17.0 | (7.72) | 15.5 | (34.6) |
| t1/2sc,1 | (days) | 11.3 | (9.78) | 34.0 | (21.3) |
| t1/2,sc,2 | (days) | 7.92 | (17.9) | 61.6 | (25.2) |
| CL/F | (l h−1) | 63.2 | (4.13) | 21.6 | (10.4) |
| Q/F | (l h−1) | 76.3 | (10.5) | – | – |
| Vc/F | (l) | 640 | (5.77) | 32.9 | (14.1) |
| Vp/F | (l) | 698 | (7.95) | – | – |
| Fr | (–) | 0.605 | (2.08) | 6.60* | (27.6) |
| t | (h) | 1.77 | (4.45) | – | – |
| Base | (ng ml−1) | 0.0107 | (5.02) | – | – |
| σprop | (%) | 27.8 | (4.78) | – | – |
| Degarelix pharmacokinetic parameters | |||||
| t1/2,fast | (days) | 1.98 | (6.17) | – | – |
| (days) | 53.3 | (9.47) | 43.9 | (7.30) | |
| (days) | 73.7 | (4.74) | 44.4 | (7.30) | |
| (days) | 95.4 | (7.60) | 44.6 | (7.30) | |
| CL | (L/ h) | 2.54 | (5.43) | 28.1 | (9.61) |
| Q | (L/ h) | 6.59 | (7.36) | – | – |
| Vc | (L) | 13.2 | (9.24) | 24.6 | (32.3) |
| Vp | (L) | 36.1 | (4.99) | – | – |
| Fr20 | (–) | 0.129 | (9.46) | 34.9* | (10.5) |
| Fr40 | (–) | 0.0573 | (6.30) | 37.8* | (10.5) |
| Fr60 | (–) | 0.0417 | (8.20) | 38.4* | (10.5) |
| F20 | (–) | 0.397 | (7.71) | 18.4* | (13.4) |
| F40 | (–) | 0.240 | (6.83) | 23.2* | (13.4) |
| F60 | (–) | 0.198 | (8.18) | 24.5* | (13.4) |
| σProp | (%) | 28.7 | (2.53) | – | – |
*
Approximate interindividual variability (IIV) for logit-transformed parameter, i.e. CV(θ) = (1 − θ)ωθ.