TABLE 3

Physicochemical properties of opioid agonists with different brain penetrations

Brain penetration data were obtained from Kalvass et al. (2007a,b,c).

DrugLog P/D7.4HBAHBDTPSAKpbrainKpuu,braint1/2 for equilibration
Å2min
Sufentanil3.4/2.030332.11.24.3
Fentanyl4.1/2.720242.30.94.9
Loperamide4.4/2.431440.10.227
Morphine0.9/−0.842531.10.974
Alfentanil2.2/1.960810.20.31.0
Meperidine2.9/2.220296.82.45.4
Methadone3.9/1.420203.30.69.6
  • HBA, hydrogen bond acceptor; HBD, hydrogen bond donor; t1/2, half-life.