Methods & Processes Sponsored by
Tony O'Lenick explains that the basic categories of cosmetic formulas include: solutions, creams/emulsions, lotions, ointments/pastes, suspensions, tablets, powders, gels, sticks and aerosols. Here, he turns to Perry Romanowski, of Brains Publishing, to discuss the differences between these ten types.
These are the simplest type of cosmetic formulas and are used for a wide range of products such as shampoos, body washes, hand cleansers, colognes, etc. They are homogeneous mixtures of soluble ingredients. To make them, the main container is filled with the main diluent (usually water), and the rest of the ingredients are mixed into the diluent. Sometimes warming the system slightly will increase the speed at which a formulator can make them.
The majority of cosmetics use raw materials that are not compatible, and when this incompatibility occurs, a cream or emulsion is used. Emulsions are pseudo-stable mixtures of immiscible liquids dispersed in another liquid. They are used for products such as hand moisturizers, makeup, hair conditioners, sunscreens, etc. To create them, a formulator needs three formula components including an oil phase, an aqueous phase and an emulsifier. The formulas are made by heating the oil and water phases separately, then mixing them together (along with the emulsifier). Once they are hot, they are cooled with thorough mixing. The result is a cream with tiny particles dispersed in the diluent phase.
Creams are not always appropriate for some applications because they can be heavy or greasy. In these cases, the lotion form is used. Lotions essentially are thin creams. They are used for facial moisturizers, leave-in hair conditioners and moisturizing cleansers. As lotions are emulsions, they are formulated the same way as a cream. They are generally easier to formulate because the formulator does not need to wait for the emulsion to thicken upon cooling.
These are very thick products that are used for hair styling and medicated skin products. Usually they are anhydrous (meaning they do not contain water), sticky and greasy. Common ingredients used to create pastes include petrolatum, lanolin or dimethicone. Making them is a simple matter of heating up the raw materials and rapidly mixing them until they are dispersed.