title: Pharmacokinetic comparisons of five ephedrine alkaloids following oral administration of four different Mahuang-Guizhi herb-pair aqueous extracts ratios in rats.
abstract: BACKGROUND
  Herba Ephedra (Mahuang in Chinese), is derived from dried Ephedra sinica Stapf stems and has been widely used to treat the common cold, coughs, asthma, and edema for thousands of years. The Mahuang-Guizhi herb-pair is a famous formula composed of Mahuang and Ramulus Cinnamomi (Guizhi in Chinese, the dried twig of Cinnamomum cassia Presl.), used to improve pharmacological effects and reduce toxicity. In order to investigate the influence of Mahuang-Guizhi herb-pair ratios on bioavailability, the plasma pharmacokinetics profiles of five ephedrine alkaloids were compared following oral administration of four different ratios to rats.
  
  
  METHODS
  Sprague-Dawley rats were randomly assigned to four groups and orally administered Mahuang-Guizhi (ratios 3:0; 3:1; 3:2; 3:4, w/w). Assays for five ephedrine alkaloids (ephedrine, pseudoephedrine, methylephedrine, norephedrine, and norpseudoephedrine) were developed and validated using ultra-high-performance liquid chromatography tandem mass spectrometry coupled with liquid-liquid extraction.
  
  
  RESULTS
  Key pharmacokinetic parameters of the five ephedrine alkaloids (maximal plasma concentration, mean residence time, and half-life) were significantly different (p<0.05) after oral administration of Mahuang-Guizhi herb-pair ratios, as compared to those of Mahuang.
  
  
  CONCLUSIONS
  Ephedrine alkaloid pharmacokinetic differences in rat plasma could help explain previous findings of pharmacological and toxicity differences between Mahuang and Mahuang-Guizhi herb-pair preparations. These results could facilitate future studies to increase the efficacy and decrease the toxicity of Mahuang and Guizhi.
authors.affiliation: School of Chinese Medical Sciences, Southern Medical University, 510515 Guangzhou, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wei
authors.affiliation: School of Chinese Medical Sciences, Southern Medical University, 510515 Guangzhou, PR China.
authors.forename: Hui-ling
authors.initials: HL
authors.lastname: Huo
authors.affiliation: School of Chinese Medical Sciences, Southern Medical University, 510515 Guangzhou, PR China.
authors.forename: Qing-hai
authors.initials: QH
authors.lastname: Ma
authors.affiliation: School of Chinese Medical Sciences, Southern Medical University, 510515 Guangzhou, PR China.
authors.forename: Han-cheng
authors.initials: HC
authors.lastname: Li
authors.affiliation: School of Chinese Medical Sciences, Southern Medical University, 510515 Guangzhou, PR China; Guangdong Province Key Laboratory of Chinese Medicine Pharmaceutics, Southern Medical University, Guangzhou, PR China. Electronic address: xiaoxing0610@163.com.
authors.forename: Xue-feng
authors.initials: XF
authors.lastname: Xing
authors.affiliation: School of Chinese Medical Sciences, Southern Medical University, 510515 Guangzhou, PR China; Guangdong Province Key Laboratory of Chinese Medicine Pharmaceutics, Southern Medical University, Guangzhou, PR China.
authors.forename: Xiao-mei
authors.initials: XM
authors.lastname: Tan
authors.affiliation: School of Chinese Medical Sciences, Southern Medical University, 510515 Guangzhou, PR China; Guangdong Province Key Laboratory of Chinese Medicine Pharmaceutics, Southern Medical University, Guangzhou, PR China. Electronic address: Luojb_smu@163.com.
authors.forename: Jia-bo
authors.initials: JB
authors.lastname: Luo
mesh_terms: D000284:Administration, Oral; D000470:Alkaloids / Q000008:administration & dosage / Q000302:isolation & purification / Q000493:pharmacokinetics*; D000818:Animals; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D032904:Cinnamomum aromaticum / Q000737:chemistry*; D029790:Ephedra sinica / Q000737:chemistry*; D006207:Half-Life; D059625:Liquid-Liquid Extraction; D051381:Rats; D017207:Rats, Sprague-Dawley; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D000470:Alkaloids
keywords: Acetonitrile (PubChem CID:6342); Amantadine hydrochloride (PubChem CID:64150); Diethyl ether (PubChem CID:3283); Ephedrine alkaloids; Ephedrine hydrochloride (PubChem CID:65326); Formic acid (PubChem CID:284); Mahuang–Guizhi herb-pair; Methylene chloride (PubChem CID:6344); Methylephedrine hydrochloride (PubChem CID:198190); Norephedrine hydrochloride (PubChem CID:62943); Norpseudoephedrine hydrochloride (PubChem CID:92920); Pharmacokinetic; Prescription compatibility; Pseudoephedrine hydrochloride (PubChem CID:9581); Sodium carbonate (PubChem CID:10340); UPLC–MS/MS