The alpha carbon oxidation of some phencyclidine analogues by rat tissue and its pharmacological implications

1. The metabolism of phencyclidine (PCP) and three congeners, differing in the structure of the amine moiety, by liver microsomes from phenobarbital-pretreated rats, was determined. 2. The metabolites generated by sequential oxidation of the two carbons alpha to the nitrogen were measured for PCP and its diethyl analogue (PCDE). 3. Alpha hydroxylation was a dominant metabolic pathway for PCDE, but less so for PCP. 4. Evaluation of affinities for the N-methyl-D-aspartate (NMDA) and sigma receptors in vitro showed that the product of alpha-hydroxylation of PCDE, phenylcyclohexylethylamine (PCE), was very potent. 5. Therefore, the in vivo actions of PCDE could include a significant contribution by PCE. 6. All congeners formed phenylcyclohexylamine (PCA), the product of a second alpha-hydroxylation, with PCDE and the pyrrolidine analogue generating the largest proportion.