These Q3 attributes (discussed furt

These Q3 attributes (discussed further in section III of this guidance) may confer important functionality to topical products. For example, the functional properties of a petrolatum-based ointment may include a relatively high occlusivity, high apparent viscosity, and long residence time at the site of administration. By contrast, the functional properties of an alcohol-based gel may include a relatively low occlusivity, low viscosity, and relatively rapid evaporation with characteristically rapid changes in the thermodynamic activity of the active ingredient(s) and in the rate of active ingredient delivery into the skin.