Table 3.
PK Parameters
| Age Groups (N) | |||||||
|---|---|---|---|---|---|---|---|
| 0–2 (3) | 3–5 (10) | 6–11 (7) | 12–17 (4) | Adult (53) | |||
| Description | Parameter | Units | Mean (CV%) | ||||
| Formulation-dependent parameters | |||||||
| Absorption rate constant (NaPBA) | KA1 | 1/h | 1.34 (56) | 1.45 (40) | 1.88 (39) | 1.8 (33) | 1.43 (51) |
| Absorption rate constant (GPB) | KA2 | 1/h | 0.31 (48) | 0.42 (24) | 0.44 (39) | 0.3 (53) | 0.35 (54) |
| PBA % metabolized presystemically (NaPBA) | Alpha/(1 + alpha) × 100 | % | 3 (25) | 4 (15) | 6 (17) | 9 (19) | 10 (17) |
| PBA % metabolized presystemically (GPB) | Alpha/(1 + alpha) × 100 | % | 8 (24) | 12 (14) | 17 (15) | 24 (16) | 27 (14) |
| PAA % metabolized to PAGN presystemically (NaPBA) | Beta/(1 + beta) × 100 | % | 100 | 100 | 100 | 100 | 100 |
| PAA % metabolized to PAGN presystemically (GPB) | Beta/(1 + beta) × 100 | % | 53 (13) | 63 (6) | 72 (5) | 79 (4) | 82 (3) |
| PBA | |||||||
| Clearance for PBA | CLB | L/h | 3.5 (23) | 5.9 (31) | 6.6 (27) | 11.8 (23) | 13.6 (38) |
| Volume of distribution for PBA | VPB | L | 3.6 (39) | 6.2 (100) | 9.2 (99) | 9.2 (40) | 14.7 (52) |
| PAA | |||||||
| Vmax for PAA to PAGN conversion | VMPA | µmol/h | 1368 (26) | 2092 (16) | 3166 (18) | 4697 (21) | 5559 (19) |
| Km for PAA to PAGN conversion | KMPA | µM | 193 | 193 | 193 | 193 | 193 |
| Clearance for PAA calculated as Vmax/Km (linear portion) | L/h | 7.1 | 10.9 | 16.4 | 24.4 | 28.9 | |
| Volume of Distribution for PAA | VPA | L | 6.6 (44) | 12.8 (35) | 15.7 (38) | 57.6 (85) | 47.2 (71) |
| PAGN | |||||||
| Clearance for PAGN | CLG | L/h | 3 (23) | 5 (22) | 7.7 (12) | 12.7 (18) | 11.9 (25) |
| Volume of distribution for PAGN | VPG | L | 6.1 (26) | 8.7 (20) | 18.7 (46) | 20.9 (18) | 24.6 (24) |
Note: Km is the same for all age groups because no variability parameter (BSV) was estimated for KMPA.