Table 1.

Different formulations of IHS and feature comparison.

The Formulations of IHS	Inactive Ingredients	Characteristics	Ref.
Liquid formulations	Humectant, fragrance, colorant.	Widely available, but with low viscosity and hard to dispense.	[17]
Spray formulations	Valve actuation, humectant, fragrance, colorant.	Higher flammability risk at room temperature.	[18]
Foam formulations	Foaming agent, humectant, fragrance, colorant.	Longer drying time, difficult to eliminate the feeling of dissimilarity and more expensive than gel.	[19,23]
Gel formulations	Emollients, thickeners, neutralizers, chelators, fragrances, and dyes or colorants.	With better antimicrobial action and fast drying time, formation of a protective layer on the application site.	[20,22]