Cocapropylene (propylcocaine) formation by human liver in vitro.

Formation of cocapropylene (CP), the n-propyl analogue of cocaine, by human liver has been demonstrated for the first time through incubation of whole liver homogenates with cocaine (COC) and n-propanol (PrOH). The formation of CP was noted by 30 min in each case, and it continued throughout the 6-h study period. The concentration of COC declined throughout each incubation. Sodium fluoride was found to inhibit completely the formation of CP. For control purposes, the capability of each liver to generate cocaethylene (CE), the known transesterification product of COC and ethanol (EtOH), was established by separate incubation of the homogenate with COC and EtOH. Concentrations of COC, CP, and CE in the respective homogenates were measured by reversed-phase high-performance liquid chromatography, whereas those of EtOH and PrOH were measured by gas-liquid chromatography.