Systemic bioavailability of fluticasone propionate administered as nasal drops and aqueous nasal spray formulations

Aims To measure and compare the systemic bioavailability of fluticasone propionate aqueous nasal spray and a new nasal drop formulation, using a sensitive analytical method and high dose regimen. Methods Volunteers received four 800 mug doses of fluticasone propionate as a nasal spray or drops over 2 days, separated by an 8 h dose interval. On day 2, blood samples were collected for assay of fluticasone propionate plasma concentrations. Results The mean systemic exposure, for both formulations was 8.5 pg ml(-1) h (drops) and 67.5 pg ml(-1) h (spray). Mean absolute bioavailabilities were estimated to be 0.06% (drops) and 0.51% (spray), by reference to historical intravenous data. Conclusions Both formulations exhibited low systemic bioavailability, even at 12 times the normal daily dose. The bioavailability from the nasal drops was approximately eight times lower than from the nasal spray.