RT Journal Article
SR Electronic
T1 Transport of cefodizime, a novel third generation cephalosporin antibiotic, in isolated rat choroid plexus.
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 324
OP 328
VO 250
IS 1
A1 Nohjoh, T
A1 Suzuki, H
A1 Sawada, Y
A1 Sugiyama, Y
A1 Iga, T
A1 Hanano, M
YR 1989
UL http://jpet.aspetjournals.org/content/250/1/324.abstract
AB To characterize the transport system by which cephalosporin antibiotics are accumulated by the choroid plexus, kinetic analysis of cefodizime transport was performed. Accumulation of cefodizime was against an electrochemical potential gradient via a saturable process (Km = 470 microM, Vmax = 174 nmol/ml of tissue per min) that was inhibited by metabolic inhibitors (KCN and 2,4-dinitrophenol), hypothermia, a sulfhydryl reagent (p-hydroxymer-curibenzoic acid) and anion transport inhibitors (probenecid and 4,4'-diisothiocyanostilbene -2,2'-disulfonic acid). Accumulation of cefodizime was inhibited competitively by benzylpenicillin with an inhibition constant of aproximately 100 microM. Cefodizime inhibited competitively the accumulation of benzylpenicillin with an inhibition constant of approximately 500 microM. Kinetic analysis using 16 kinds of beta-lactam antibiotics also supported the view 1) that the transport system of cefodizime is shared by benzylpenicillin and 2) that these beta-lactam antibiotics are transported via a common transport system. These findings indicate that the major transport system of cephalosporin antibiotics in the rat choroid plexus is via a carrier-mediated active anion transport process. The affinity of beta-lactam antibiotics for this transport system in the choroid plexus may be a major factor in determining their pharmacokinetics in the cerebrospinal fluid.