[Comparative measurement of cocaine and its metabolites in blood, cerebrospinal fluid and the brain].

This study investigated the transfer of cocaine and its metabolites from plasma into the cerebrospinal fluid. The concentration of cocaine and its metabolites in plasma and cerebrospinal fluid was determined by radioimmunoassay because this method only, the sum of the drug and metabolites restored. In sheeps a sublethal cocaine hydrochloride dose (2,4 mg/kg b. wt.) was administered intraarterial daily for up to 8 days. In the first hours after administration the concentration of cocaine in cerebrospinal fluid was low. It is supposed that a barrier against the transport of cocaine from blood into cerebrospinal fluid exists. After intrathecal administration a delay of transport could from CSF to blood not be seen.