Table 3.
Summary of the effect of buffer pH on the release kinetics of 1, 2, and 3 when protected from light and after light exposure (photoactivated) in phosphate buffer. Uncertainty expressed as standard error (N = 3).
| 1 | 2 | 3a | 1 | 2 | ||
|---|---|---|---|---|---|---|
| Dark | Photoactivated | |||||
| pH 7.4 | t1/2 (hrs) | 2.1 ± 0.2 | 8.8 ± 0.6 | 0.2 ± 0.07 (13.5 ± 4.8) | 9.9 ± 1.1 | 13.9 ± 1.8 |
| Release (%) | 90.0 | 77.0 | 45.2 (51.9) | 65.8 | 55.9 | |
|
| ||||||
| pH 6.0 | t1/2 (hrs) | 1.9 ± 0.2 | 7.7 ± 0.6 | 0.2 ± 0.06 (9.0 ± 2.1) | 7.5 ± 0.7 | 10.1 ± 1.1 |
| Release (%) | 95.3 | 72.5 | 45.0 (46.4) | 70.0 | 50.3 | |
a
The release of 3 in solution with 0 mM NaCl was fit to a two-phase non-linear exponential regression. The first t1/2 value corresponds to release in the primary phase while the t1/2 value in parenthesis corresponds to release in the secondary phase. The first value for release indicates the percentage of 3 released in the primary phase while the value in parenthesis indicates the total percentage of 3 released in both phases.