LC-ESI-MS determination of guaifenesinum concentration in human plasma and its application in pharmacokinetics studies

Objective:To establish an LC-ESI-MS method for determination of guaifenesinum in human plasma and study the pharmacokinetics characteristics of it in healthy volunteers.Methods:The plasma samples were pretreated with liquid-liquid extraction in ethyl acetate.Samples were analyzed on Shimadzu Pack VP-ODS C18( 5 μm,150 mm×2.0 mm ) column,the mobile phase consisting of methanol-water(43∶ 57) containing 0.4% glacial acetic acid and 0.4 mmol·mL-1 ammonium acetate,the flow rate was 0.2 mL·min-1;column temperature was set at 35 ℃.The volume of injection was 10 μL.The analyte and internal standard Roxithromycin were both analyzed by MS in the ESI,m/z was 199.0 for guaifenesinum and 837.5 for the IS,respectively.Results:The method was linear in the concentration range of 25.0-6400.0 ng·mL-1 (r=0.9999),the absolute recovery was greater than 85%.The within-run and between-run relative standard deviation was less than 15%.Conclusion:This method is easy,sensitive,therefore,it can be used to analyze human plasma samples for application in pharmacokinetic studies and clinical therapeutic drug monitoring.