Ibuprofen gargle
The ibuprofen gargle was manufactured at the Department of Pharmacy, Kobe University Hospital. The gargle (100 mL) contained ibuprofen (600 mg, 0.6%; Tokyo Chemical Industry), sodium hydroxide (Fujifilm Wako), sodium hydrogen carbonate (Fujifilm Wako), hydrochloric acid (for pH regulation; Fujifilm Wako), glycerin (Fujifilm Wako), and flavor (Marugo). The placebo gargle formulation was designed to be similar to the ibuprofen gargle in terms of taste and appearance, but without the inclusion of ibuprofen.