Quantification of fluticasone propionate in human plasma by LC-MS/MS and its application in the pharmacokinetic study of nasal spray at clinical doses.

We developed a method for quantifying fluticasone propionate (FP) using general-purpose liquid chromatography-tandem mass spectrometry equipment to measure the plasma concentration of FP for the pharmacokinetic study of FP following the administration of a prescribed nasal spray dose (100 μg). Using ammonium acetate (0.01 M)-formic acid (pH 2.9; 499:1, v/v) and methanol as the mobile phase, 3 pg/mL of FP was quantified. The relative error and standard deviation of the lower limit of quantification were <3.1%. The intra- and interday assay reproducibility was <3.5%. After 15 min of administering 200 μg FP nasal spray as the first dose, the FP concentration detected in the plasma of the two participants was 3.99 and 3.69 pg/mL. Subsequent doses of 100 μg FP were administered twice daily. The area under the plasma concentration-time curve values after 8-10 days of repeated administration of 100 μg of FP were approximately 1.6-fold higher than those achieved following a single administration of 200 μg of FP, which confirmed drug accumulation. The bioavailability of nasal FP was estimated to be 2% and 4%. This knowledge might help in reducing anxiety among patients who avoid using FP nasal spray, fearing its adverse effects.