Extraction, separation, and detections of 14C-diazepam and 14C-metabolites from brain tissue of mature and old rats.

A rapid method for simultaneous determination of brain concentrations of diazepam and each of its three major metabolites in brain tissue by a reverse isotope dilution procedure is presented. Radiolabeled diazepam and metabolites were extracted from brain tissue of mature and senescent rats with ethyl ether. After the ether was evaporated the benzodiazepines were separated from the residue by passing the water soluble portion through C-18 bonded-phase extraction columns.