Pharmacokinetics of racemic and S(+)-ketamine administered epidurally in rabbits

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 12671468
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Anesthesiology/Resuscitation studies
• Research Institution: Tottori University
• Principal Investigator: INAGAKI Yoshimi Tottori University, Faculty of Medicine, Associate Professor, 医学部, 助教授 (40184717)
• Co-Investigator(Kenkyū-buntansha): NISHIMURA Yukiko Tottori University, Faculty of Medicine, Assistant Professor, 附属病院, 助手 (50304233) ; ISHIBE Yuichi Tottori University, Faculty of Medicine, Professor, 医学部, 教授 (40122014) ; OKAZAKI Naoto Tottori University, Faculty of Medicine, Assistant Professor (30032204)
• Project Period (FY): 2000 – 2002
• Keywords: Epidural analgesia / NMDA receptor antagonist / Racemic ketamine / S(+)-ketamine / Pharmacokinetics / 薬物動態 / 脳脊髄液

Research Abstract

Table1. Pharmacokinetic parameters from the epidural space to plasma
Pharmacokinetic parameters of both epidural racemic ketamine and S(+)-ketamine were summarized in tables 1 and 2.
<<table>>
Values are expressed as Mean+__-SD. *p<0.05, vs. S(+)-ketamine. AUC: are under the curve. Cmax: maximum concentration. Tmax: time to maximum concentration. T1/2α: distribution half time. T1/2β: elimination half time. Vd: distribution volume.
Table 2. Pharmacokinetic parameters form the epidural space to cerebrospinal fluid.
<<table>>
Values are expressed as Mean+__-SD.
S(+)-ketamine had significantly larger than AUC and smaller Vd compared with racemic ketamine in the pharmacokinetic parameters from the epidural space to plasma, which indicated that S(+)-ketamine distributed more effectively than racemic ketamine. This finding may explain that epidural S(+)-ketamine had more anesthetic or analgesic potency than epidural racemic ketamine.