Table 3. Measured and Calculated Physicochemical Properties.
| compd | tR (min)a | LogD 7.4b | cLogPc | tPSA (Å2)c |
|---|---|---|---|---|
| Leu-enkephalin | 8.44 | –0.886 ± 0.030 | –0.851 | 199.95 |
| 4 | 9.93 | –0.400 ± 0.019 | –0.52 | 197.15 |
| 8 | 9.23 | –0.363 ± 0.004 | –0.230 | 191.16 |
| morphine | 1.22 | –0.160 ± 0.005 | 0.571 | 52.93 |
a
Retention time: RP-HPLC was performed using an Agilent Eclipse Plus C-18 column, 50 mm × 3.0 mm, 1.8 μm. Solvent A, 0.1% TFA in water; solvent B, 0.1% TFA in acetonitrile; 2–98% B in A over 20 min; flow rate, 0.4 mL/min.
b
Partition coefficient measured using the shake-flask method with PBS pH = 7.4.
c
Calculated using ChemBioDraw 12.0; tPSA, topological polar surface area.