[Determination of lidocaine and its metabolites in human plasma by liquid chromatography in combination with tandem mass spectrometry].
OBJECTIVE
To establish a liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method for the determination of lidocaine (LDC) and its metabolites, monoethylglycinexylidide (MEGX) and glycinexylidide (GX), in human plasma. METHODS; The assay was conducted with an API 3000 HPLC-MS/MS system consisted of a Ultimate C18 column (50 x 4.6 mm, 5 microm). The mobile phase consisted of methanol: 5 mmol/ L ammonium acetate (50:50, pH was adjusted to 5.0 by formic acid) and the flow rate was set at 0.2 mL/min. The alkalinized sample was extracted with ethyl acetate. After evaporation of the organic layer, the residue was dissolved in mobile phase and the drug was determined by HPLC-MS/MS using electrospray ionization.


RESULTS
The calibration curve was linear in a range from 15.625 to 2000 ng/mL for LDC. Linear calibration curves were obtained in the range of 1.5625 to 200 ng/mL for both for MEGX and GX. The limit of quantification for LDC, MEGX and GX was set at 15.625, 1.5625 and 1.5625 ng/mL.


CONCLUSIONS
This method for the quantitative determination of lidocaine and its metabolites in human plasma is simple, rapid, sensitive and accurate. Therefore it can be used for the determination of lidocaine and its metabolites in clinical practice.
Xiang
Jin
J
Institute of Clinical Pharmacology, GCP Center, West China Hospital, Sichuan University, Chendu 610041, China.
Zhang
Cheng
C
Yu
Qin
Q
Liang
Mao-Zhi
MZ
Qin
Yong-Ping
YP
Nan
Feng
F
D000779:Anesthetics, Local / Q000097:blood* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D008012:Lidocaine / Q000031:analogs & derivatives / Q000097:blood* / Q000378:metabolism; D053719:Tandem Mass Spectrometry / Q000379:methods*
D000779:Anesthetics, Local; D008012:Lidocaine; C001306:glycinexylidide; C001173:monoethylglycinexylidide