Table 1.
Monoisotopic molecular weight (g/mol), pKa and Log P of selected natural, semi-synthetic and synthetic opioids.
| Group | Analyte | Monoisotipic molecular weight (g/mol) | pKa | Log P |
|---|---|---|---|---|
| Natural and semi-synthetic opioids | Morphine | 285.136 | 8.2 | 0.9 |
| Codeine | 299.152 | 9.2 | 1.3 | |
| Hydrocodone | 299.152 | 8.6 | 2.0 | |
| Hydromorphone | 285.133 | 8.6 | 1.6 | |
| Oxycodone | 315.147 | 8.2 | 1.0 | |
| Oxymorphone | 301.131 | 10.9 | 0.8 | |
| Buprenorphine | 467.300 | 7.5 | 4.5 | |
| Synthetic opioids | Fentanyl | 336.220 | 8.8 | 3.8 |
| Methadone | 309.445 | 9.1 | 5.0 | |
| Tramadol | 263.189 | 9.2 | 2.5 | |
| Synthetic opioids-Fentanyl derivatives | alphamethylacetylfentanyl; acetyl-alpha-methylfentanyl | 336.220 | 9.01 | 3.5 |
| Alfentanil | 416.253 | 7.5 | 2.8 | |
| Butyryl fentanyl; butyr fentanyl |
350.235 | 8.77 | 4.3 | |
| Carfentanil | 394.225 | 8.05 | 3.7 | |
| 3-methylcarfentanil; lofentanil |
408.241 | 8.36 | 4.2 | |
| 4-fluorofentanyl; 4-FBF; para-fluorofentanyl |
354.210 | 8.74 | 4.0 | |
| beta-hydroxyfentanyl | 352.215 | 8.28 | 2.9 | |
| alpha-methylfentanyl | 350.235 | 9 | 4.2 | |
| cis-3-methylfentanyl; 3-MF; mefentanyl |
350.235 | 9.08 | 4.3 | |
| beta-hydroxy-3-methylfentanyl; ohmefentanyl | 366.230 | 8.59 | 3.4 | |
| Remifentanil | 376.199 | 7.51 | 1.5 | |
| Sufentanil | 386.202 | 8.86 | 3.6 | |
| 3-methylthiofentanyl | 356.192 | 9.07 | 4.2 |