Table 2.
Long-term dissolution parameters (mean ± standard deviation) for tungsten-containing materials after immersion in artificial airway epithelial lining fluid (pH 7.4) for 72 hours
| As Received | Dispersed | Mixture with Cobalt | ||||
|---|---|---|---|---|---|---|
| Powder | t1/2 (days) | k [g/(cm2·day)] | t1/2 (days) | k [g/(cm2day)] | t1/2 (days) | k [g/(cm2·day)] |
| WO3 | 4 ± 1 | 2.5 ± 0.3 × 10-5 | 11a | 0.9 × 10-5 | 79 ± 23 | 1.3 ± 0.4 × 10-6 |
| WO2.98 | 1 ± 0 | 6.0 ± 1.2 × 10-6 | 1 ± 0 | 6.0 ± 2.3 × 10-6 | 10 ± 2 | 6.5 ± 1.6 × 10-7 |
| WO2.81 | 11 ± 2 | 2.3 ± 0.3 × 10-6 | 13 ± 1 | 1.9 ± 0.1 × 10-6 | 71 ± 6 | 3.5 ± 0.3 × 10-7 |
| WO2.66b | 56 ± 10 | 8.4 ± 1.7 × 10-7 | 41 ± 2 | 1.1 ± 0.1 × 10-6 | 72 ± 22 | 6.8 ± 1.8 × 10-7 |
| WO2.51 | 81 ± 4 | 4.1 ± 0.2 × 10-7 | 50 ± 14 | 6.9 ± 1.7 × 10-7 | 89 ± 13 | 3.8 ± 0.6 × 10-7 |
| W | 19 ± 2 | 5.4 ± 0.5 × 10-6 | --c | -- | -- | -- |
a Result for WO3 in dispersed state is for n = 1 sample
b Values for t1/2 (days) and k [g/(cm2·day)] calculated using surface-area-limited dissolution model: 30 ± 6, 1.6 ± 0.3 × 10-6 (as-received); 22 ± 2, 2.1 ± 0.2 × 10-6 (dispersed); 37 ± 11, 1.3 ± 0.3 × 10-6 (mixture).
c Not applicable for the tungsten metal samples