Final ProgramCPSA 2011
Science and Technology Coming Together to Make a Difference
October 3 - 6, 2011
Bucks County Sheraton Hotel
Langhorne, PA
Poster Abstract #07
LC/MS/MS Quantification of Fluticasone Propionate in Human Plasma at the fg/mL Level
Waters Corporation, Milford, MA
Fluticasone propionate is a trifluorinated corticosteroid that has potent anti-inflammatory activity and is used to treat asthma and chronic obstructive pulmonary disease. As Fluticasone undergoes metabolism, there is negligible systemic exposure. For accurate measurement of pharmacokinetics, it is necessary to detect this compound in the sub- pg/mL level. Historically, LC/MS/MS instrumentation has not provided sufficient sensitivity to quantify the plasma concentrations of this compound at the fg/mL level. In this paper, we demonstrate the quantification of fluticasone at the sub pg/mL level using LC/MS/MS.
As Fluticasone propionate is dosed by the inhaled route, the majority of the drug is directed to the lungs and the remainder is eliminated in the liver via hydrolysis of the S- fluoromethyl carbothioate function to form the inactive 17 -carboxylic acid metabolite. These factors result in circulating levels of the drug in the 0.5pg/mL - 1pg/mL level. The high protein binding ability also presents a challenge when developing a sensitive assay.
The samples were prepared by solid phase extraction. 375 L of plasma was diluted with aqueous solution containing Stable Label Isotope (SLI) internal standard for both analytes and mixed well. The samples were applied to an OASIS HLB Elution plate, washed with an organo-aqueous solution and eluted in a solution of methanol- acetonitrile. This eluted solution was diluted with aqueous buffer prior to injection onto the ACQUITY UPLC/Xevo TQ-S system. The sub 2 m separation resolved the active compound from endogenous interferences and metabolites. The novel ion guide optics in the MS resulted in sufficient sensitivity to detect and quantify fluticasone propionate at 0.75 pg/mL. The peak width of the fluticasone analyte was calculated to be approximately 3 seconds at the base, allowing for a high resolution separation of the analyte from the endogenous material in the sample. The calibration was shown to be linear over the range of 0.75 - 15pg/mL, with the signal to noise ratio of the 0.75 pg/mL being in excess of 5:1. This level of sensitivity allows for the accurate determination of the pharmacokinetics of the Fluticasone propionate in plasma.