Biotransformation of norcocaine to norcocaine nitroxide by rat brain microsomes.

In the mid 1970's, norcocaine was identified as a metabolite of cocaine in rat brain tissue. We extend these studies by demonstrating that rat brain FAD-containing monooxygenase metabolizes norcocaine to N-hydroxynorcocaine. This hydroxylamine is then further oxidized to the nitroxyl free radical norcocaine nitroxide by rat brain cytochrome P-450. Brain microsomal reduction of norcocaine nitroxide leads to the generation of superoxide. Finally, incubation of rat brain microsomes with either N-hydroxynorcocaine or norcocaine nitroxide leads to significant lipid peroxidation as monitored by spin-trapping techniques.