Cetrimonium Bromide is a preservative.

This ingredient is derived from caprylic and capric acids. It is an emulsifier with emollient properties.

According to the manufacturer, it is hydrophilic and soluble in aqueous solutions (water). They also state this ingredient is stable in a medium pH range (~5 - 8).

Water. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.

So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.