title: Evaluation of high-performance liquid chromatography and mass spectrometry method for pharmacokinetic study of local anesthetic ropivacaine in plasma.
abstract: We studied the viability of high-performance liquid chromatography and mass spectrometry (LC/MS) as a selective and sensitive analytical method for measuring blood concentrations of the local anesthetic ropivacaine. Ropivacaine was effectively separated using a reverse-phase column and monitored at 275 m/z ion. The LC/MS method allowed measurement of concentrations of ropivacaine of lower than 75 ng/mL. The standard curve was linear and in the range of <1.5 microg/mL. Recovery of ropivacaine in plasma samples was over 90% after precipitation of plasma protein with trichloroacetic acid. The method was tested on the pharmacokinetics of plasma ropivacaine after single intravenous or subcutaneous administration in rabbits. The pharmacokinetic parameters showed a one-compartment model and a mean elimination half-life of 0.54+/-0.05 h and 2.83+/-0.51 h after administration at doses of 0.4 mg/kg, i.v. and 5 mg/kg, s.c., respectively. These values were in approximate agreement with previously obtained results in dogs. The results of the present study demonstrated that the LC/MS method was highly selective and sensitive for the measurement of ropivacaine, indicating that it offers a useful tool for monitoring the therapeutic effects and determining the pharmacokinetic parameters of this drug in blood.
authors.affiliation: Department of Pharmacology, Tokyo Dental College, Chiba, Japan. sawaki@tdc.ac.jp
authors.forename: Kohei
authors.initials: K
authors.lastname: Sawaki
authors.forename: Migiwa
authors.initials: M
authors.lastname: Okubo
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimomiya
authors.forename: Eri
authors.initials: E
authors.lastname: Tukagoshi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sakai
authors.forename: Takaki
authors.initials: T
authors.lastname: Yamazaki
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kenmochi
authors.forename: Mariko
authors.initials: M
authors.lastname: Miyao
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Kaneko
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ichinohe
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Kawaguchi
mesh_terms: D000577:Amides / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics; D000779:Anesthetics, Local / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004285:Dogs; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D011817:Rabbits; D000077212:Ropivacaine
chemical_list: D000577:Amides; D000779:Anesthetics, Local; D000077212:Ropivacaine