RT Journal Article SR Electronic T1 Ceftriaxone pharmacokinetics in the central nervous system. JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 380 OP 383 VO 236 IS 2 A1 R Spector YR 1986 UL http://jpet.aspetjournals.org/content/236/2/380.abstract AB The transport and metabolism of ceftriaxone was studied in vitro in the isolated choroid plexus and in vivo in New Zealand White rabbits. In vitro, [14C]ceftriaxone was accumulated by a saturable, probenecid-sensitive system in choroid plexus, although much less readily than [14C]penicillin G. Ceftriaxone was also a much less potent inhibitor of [14C]penicillin G accumulation by the isolated choroid plexus than penicillin G itself (IC50 = 1.6 vs. 0.07 mM, respectively). In vivo, 2 hr after intraventricular injection, [14C]ceftriaxone was not metabolized or cleared from the cerebrospinal fluid more rapidly than [3H]mannitol, a molecule transported in the central nervous system by simple diffusion. These in vitro and in vivo results show that ceftriaxone, unlike penicillin G, has minimal affinity for the choroid plexus active transport system that transfers most penicillins and cephalosporins from cerebrospinal fluid to blood.