Pharmaceutical Research

, Volume 20, Issue 8, pp 1293–1301 | Cite as

Pharmacokinetic-Pharmacodynamic Relationships of (2S,3S)-Valnoctamide and Its Stereoisomer (2R,3S)-Valnoctamide in Rodent Models of Epilepsy

  • Nina Isoherranen
  • H. Steve White
  • Brian D. Klein
  • Michael Roeder
  • José H. Woodhead
  • Volker Schurig
  • Boris Yagen
  • Meir Bialer


Purpose. Racemic valnoctamide (VCD) is a central nervous system- active drug commercially available in Europe. VCD possesses two chiral centers and, therefore, it exists as a mixture of four stereoisomers. The purpose of this study was to evaluate the anticonvulsant activity of two VCD stereoisomers in comparison with VCD (racemate), valpromide (VPD), and valproic acid (VPA) and to study their pharmacokinetic-pharmacodynamic relationships.

Methods. The ability of racemic VCD, (2S,3S)-VCD, (2R,3S)-VCD and VPD to block partial seizures was studied in the 6Hz psychomotor seizure model in mice and in the hippocampal kindled rat. The ability of (2S,3S)-VCD and (2R,3S)-VCD to prevent generalized seizures was evaluated in the maximum electroshock (MES) and subcutaneous metrazole (sc Met) seizure tests. The PK of (2S,3S)-VCD, (2R,3S)-VCD, and VPD was studied in the mice utilized in the 6Hz model.

Results. All of the tested compounds were effective in the models tested. No significant difference in ED50 values was observed but the plasma and brain EC50 values of (2R,3S)-VCD in the 6Hz model at 32 mA stimulation were 2-fold higher than the EC50 values of (2S,3S)-VCD. An excellent pharmacokinetic-pharmacodynamic correlation was found between the plasma and brain concentrations of the VCD stereoisomers and their anticonvulsant effect in mice. Stereoselectivity was observed in clearance, volume of distribution, and in brain-to-plasma AUC ratio at a dose of 25 mg/kg, but the difference disappeared at higher doses as the clearance of the stereoisomers decreased and their half-life increased. For (2R,3S)-VCD the brain-to-plasma AUC ratio doubled at the tested dose range, while it remained constant for (2S,3S)-VCD.

Conclusions. Racemic VCD, VPD, (2R,3S)-VCD, and (2S,3S)-VCD are effective anticonvulsants in animal models of partial seizures and are more potent than VPA. The more favorable brain penetration of (2S,3S)-VCD and its lower EC50 value in the 6Hz test provides one advantage over (2R,3S)-VCD as a new antiepileptic drug.

anticonvulsant activity stereoselectivity valproic acid valnoctamide valpromide pharmacokinetics 


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Copyright information

© Plenum Publishing Corporation 2003

Authors and Affiliations

  • Nina Isoherranen
    • 1
  • H. Steve White
    • 2
  • Brian D. Klein
    • 2
  • Michael Roeder
    • 3
  • José H. Woodhead
    • 2
  • Volker Schurig
    • 3
  • Boris Yagen
    • 4
  • Meir Bialer
    • 1
  1. 1.Department of Pharmaceutics, School of PharmacyHebrew University of JerusalemJerusalemIsrael
  2. 2.Anticonvulsant Drug Development Program, Department of Pharmacology and ToxicologyUniversity of UtahSalt Lake City
  3. 3.Institute of Organic ChemistryUniversity of TuebingenGermany
  4. 4.Department of Natural Products and Medicinal Chemistry, School of Pharmacy, Faculty of MedicineHebrew University of JerusalemJerusalemIsrael

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