TABLE 8

Retro-reduction of oxycodone N-oxide by human liver microsomes (pH 7.4)

Values are expressed as means ± S.D., mean of four determinations, pH 7.4, 10-min incubation.

Human Liver MicrosomesOxycodoneOxycodone N-OxideNoroxycodoneOxymorphoneNoroxymorphone
(nmol/ml)/mg proteinnmol/ml(nmol/ml)/mg protein
HK37a48.6 ± 3.1115.9 ± 5.87.5 ± 0.50.2 ± 0.01ND
HH18b5.0 ± 0.29.4 ± 0.50.6 ± 0.02NDND
  • ND, not detected.

  • a Oxycodone N-oxide was present at 200 µM.

  • b Oxycodone N-oxide was present at 20 µM.