TABLE 7.
Bidirectional permeability of naloxone across MDCKII cells
The Papp values are mean (%CV), n = 3. 3H-Mannitol Papp = 0.41–1.11 × 10−6 cm/s; 14C-caffeine Papp = 15.5–53.5 × 10−6 cm/s. The efflux ratio represents the Papp of the basolateral-to-apical direction divided by the Papp of the apical-to-basolateral direction.
| Concentration |
Papp (×10−6 cm/s) |
Efflux Ratio | |
|---|---|---|---|
| A to B | B to A | ||
| Apical and basolateral (pH = 7.4) | |||
| Naloxone (10 µM) | 30.6 (5.2) | 31.5 (10.8) | 1.03 |
| Naloxone (10 µM)/naltrexone (500 µM) | 39.6 (10.9) | 23.7 (3.8) | 0.60 |
| Naloxone (500 µM) | 25.3 (9.5) | 48.3 (3.1) | 1.91 |
| Naloxone (500 µM)/naltrexone (500 µM) | 19.7 (9.1) | 37.3 (0.8) | 1.90 |
| Apical (pH = 5.5)/basolateral (pH = 7.4) | |||
| Naloxone (10 µM) | 6.48 (25.6) | 43.3 (4.6) | 6.69 |
| Naloxone (10 µM)/naltrexone (500 µM) | 5.83 (8.7) | 62.5 (1.1) | 10.7 |
| Naloxone (500 µM) | 3.29 (6.7) | 174 (6.3) | 52.9 |
| Naloxone (500 µM)/naltrexone (500 µM) | 5.08 (4.9) | 134 (6.0) | 26.3 |
A to B, apical to basolateral; B to A, basolateral to apical.