Exposure Assessment

The characterization of potential human exposure to a product/ingredient is a critical component of the safety evaluation.

For most Beauty products, the route of exposure is the skin and, inadvertently, the eye. Another indirect route of exposure could be inhalation in the shower or via spray products. An important factor that should be taken into account is absorption through the skin or mucous membranes. If absorption occurs, exposure to other organs in the body will need to be assessed.

The magnitude, duration and frequency are also important aspects in exposure. These are determined by assessing the use and potential misuse of a product. For example, a facial moisturizer will be applied to a smaller area of skin than a body moisturizer. A leave-on product like a body moisturizer will result in a longer exposure to an ingredient than a rinse-off product such as a shampoo.

P&G has decades of experience in evaluating how consumers use its products. However, if relevant data are lacking, experimental models and chemical analyses may be employed under conditions that simulate the exposure in question. In addition, a variety of mathematical models are available for estimating exposure levels from indirect sources (such as air) or specific exposure scenarios.

Below is an example of an exposure calculation of direct skin contact for Ingredient A in a face moisturizer. This ingredient has the potential for skin irritation and the objective of this risk assessment is to determine an acceptable level of Ingredient A in the moisturizer.

Exposure = (Amount of Ingredient A (mg) applied/Area of Exposed Skin on Face (cm²) = (100 mg /500 cm²) = 0.2 mg Ingredient A /cm²

This value will later be used to calculate the Margin of Safety (MOS) in Step 4.

Please note that this exposure assessment is simplified. In many cases, the number of applications per day may be considered as well as whether the product is used daily versus intermittently.

Read about the next step: Safety Testing