Product Grouping

Once the product groups have been established, the next step is to determine the so-called “worst
case” representative of each group. This may be done according to toxicity, solubility or the presence of ingredients known to be difficult to clean, such as insoluble dyes.

There is no “hard and fast” rule for this selection. In some cases, a combination of these parameters may be used. For example, if a group consisted of 5 products, four of which were cough/cold formulations and the fifth a cytotoxic product, then the cytotoxic product would be a logical choice as the worst case product.

Another example would be a group composed of 8 products of similar potency.

In this case, the worst case selection might be made on the basis of solubility. Again, the choice of the least soluble product in the group as the worst case product would be easy to defend.