Influence of mouth washing procedures on the removal of drug residues following inhalation of corticosteroids.

Mouth washing after inhalation of corticosteroids is effective for prevention of local adverse effects such as hoarseness and oropharyngeal candidiasis. To establish an optimal procedure for such mouth washing, we investigated the removal rates of drug residues remaining on the oropharyngeal mucosa using various mouth washing methods following inhalation. A beclomethasone dipropionate metered dose inhaler (BDP-MDI) (100 microg) and a fluticasone propionate dry powder inhaler (FP-DPI) (100 microg) were used. The effects of different mouth washing methods were evaluated by quantification of drugs in the expectorated rinse solution using an HPLC method. The amounts of BDP recovered in the rinse after gargling and rinsing for 5 s each were 47.1+/-13.6 microg, while they were 42.9+/-9.4 microg after rinsing alone for 10 s and 38.7+/-9.2 microg after gargling alone for 10 s. Under the same conditions, FP amounts were 32.9+/-7.3 microg, 28.9+/-2.4 microg, and 27.1+/-7.9 microg, respectively. In a comparison of washing time, the amounts of BDP recovered were 49.8+/-9.7 microg after gargling and rinsing for 2 s each, 53.5+/-10.2 microg after those for 3 s each, and 47.1+/-13.6 microg after those for 5 s each, while the amounts of FP under the same conditions were 36.4+/-2.4 microg, 33.3+/-6.4 microg, and 32.9+/-7.4 microg, respectively. As for the effect of time lag before mouth washing, the amount of BDP recovered decreased by 65.7% with a lag time of 1 min and by 5.6% after 10 min, while that of FP decreased by 51.1% with a lag time of 1 min and by 7.7% after 10 min. Our results suggest that the amount of drugs removed by mouth washing is significantly associated with the time lag between inhalation and mouth washing. We concluded that immediate gargling and rinsing after inhalation is most useful for the removal of drugs following inhalation of corticosteroids.