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Evidence-Based Complementary and Alternative Medicine
Volume 2014 (2014), Article ID 402126, 9 pages
Research Article

Pharmacokinetic Alteration of Baclofen by Multiple Oral Administration of Herbal Medicines in Rats

1School of Pharmacy, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746, Republic of Korea
2Department of Rehabilitation Medicine, School of Medicine, Catholic University of Daegu, Daegu 705-718, Republic of Korea
3Department of Pharmacy, College of Pharmacy, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea
4College of Pharmacy, Catholic University of Daegu, 13-13 Hayang-ro, Hayang-eup, Gyeongsan-si, Gyeongbuk 712-702, Republic of Korea
5Department of Cardiovascular and Neurologic Diseases, College of Oriental Medicine, Daegu Haany University, Daegu 706-060, Republic of Korea
6College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, Incheon 406-840, Republic of Korea

Received 14 April 2014; Revised 9 August 2014; Accepted 9 August 2014; Published 29 October 2014

Academic Editor: Yuping Tang

Copyright © 2014 Tae Hwan Kim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The potential pharmacokinetic (PK) interaction of conventional western drug, baclofen, and oriental medications Oyaksungisan (OY) and Achyranthes bidentata radix (AB) extract for the treatment of spasticity has been evaluated. Rats were pretreated with distilled water (DW), OY, or AB extract by oral administration every day for 7 days. After 10 min of the final dose of DW or each herbal medication, baclofen (1 mg/kg) was given by oral administration and plasma concentrations of baclofen were determined by LC/MS/MS. The plasma baclofen concentration-time profiles were then analyzed by noncompartmental analysis and a population PK model was developed. Baclofen was rapidly absorbed, showed biexponential decline with elimination half-life of 3.42–4.10 hr, and mostly excreted into urine. The PK of baclofen was not affected by AB extract pretreatment. However, significantly lower maximum plasma concentration () and longer time to reach () were observed in OY pretreated rats without changes in the area under the curve (AUC) and the fraction excreted into urine (). The absorption rate (Ka) of baclofen was significantly decreased in OY pretreated rats. These data suggested that repeated doses of OY might delay the absorption of baclofen without changes in extent of absorption, which needs further evaluation for clinical significance.