Table 2.
Pharmacokinetic Parameters by Gestational Age
| PK Parameter Median (Interquartile Range) | Second trimester (20–28 weeks gestation) (n=4) | Third Trimester (30–38 weeks gestation) (n=37) | Postpartum (6–12 weeks after delivery) (n=32) | 3rd Trimester/Postpartum Ratio Geometric Mean (90% CI) | P Value* |
|---|---|---|---|---|---|
| AUC (mg·h/L) | 1.9 (1.7, 2.5) |
2.4 (1.9, 3.1) |
3.0 (2.2, 3.7) |
0.80 (0.72, 0.89) |
0.0046 |
| CL/F (L/hr) | 72 (58, 82) |
57 (44, 71) |
46 (36, 62) |
1.25 (1.12, 1.40) |
0.0122 |
| Vd/F (L) | 1570 (941, 2501) |
1155 (1027, 1613) |
899 (652, 1236) |
1.59 (1.29, 1.97) |
0.0014 |
| Cmax (mcg/L) | 250 (202, 355) |
245 (207, 334) |
298 (200, 341) |
0.89 (0.79, 1.01) |
0.1636 |
| Tmax (hours) | 1 (1, 1.25) |
1 (1, 2) |
1 (1, 2) |
– | 0.3302 |
| T1/2 (hours) | 16.9 (15.2, 20) |
16.1 (14.4, 18.2) |
12.4 (11.7, 15.9) |
1.28 (1.07, 1.53) |
0.0213 |
| C0 (mcg/L) | 38 (35, 50) |
54 (44, 69) |
64 (42, 86) |
0.83 (0.70, 0.98) |
0.01 |
| C24 (mcg/L) | 39 (34, 49) |
54 (40, 70) |
61 (45, 79) |
0.82 (0.71, 0.96) |
0.0325 |
*
3rd trimester compared to postpartum