Table 2.
Parameter estimates for dextromethorphan and metabolites pharmacokinetic model
| Parameter | Estimate | RSE |
|---|---|---|
| Central Vd dextromethorphan (l) | 188 | 32.4% |
| Peripheral Vd dextromethorphan (l) | 1660 | 16.8% |
| k12 (h−1) | 0.213 | 7.6% |
| tlag (h) | 0.369 | 3.7% |
| CL2D6,1 (l h−1) | 1560 | 27.8% |
| CL2D6,2 (l h−1) | 362 | 46.1% |
| CL3A4,1 (l h−1) | 44.7 | 26% |
| CL3A4,2 (l h−1) | 1840 | 9.1% |
| CLHM (l h−1) | 5730 | 11.4% |
| Q1 (l h−1) | 415 | 22.1% |
| Q2 (l h−1) | 200 | 37.3% |
| k57 (h−1) | 1.11 | 19.5% |
| k75 (h−1) | 0.0815 | 28.7% |
| k68 (h−1) | 13.4 | 12.4% |
| k86 (h−1) | 0.0637 | 18.5% |
| IIV ka (shrinkage) | 31% (4%) | 39.7% |
| IIV CL2D6 (shrinkage) | 166% (-0.9%) | 29.5% |
| IIV CL3A4,1 (shrinkage) | 89.8% (19.8%) | 49.3% |
| IIV CL3A4,2 (shrinkage) | 53% (2.4%) | 27.8% |
| IIV CLHM (shrinkage) | 75.7% (6.2%) | 24.6% |
| Residual error dextromethorphan (shrinkage) | 42.9% (5.2) | 15% |
| Residual error dextrorphan (shrinkage) | 40% (7.2%) | 10.6% |
| Residual error 3-methoxymorphinan (shrinkage) | 29.7% (9.2%) | 23.2% |
| Residual error 3-hydroxymorphinan (shrinkage) | 30.7% (7%) | 12% |
| Condition number | 140 | |
IIV, inter-individual variability; RSE, relative standard error of estimate; Vd, volume of distribution.