Formulation Challenges: Managing Risks in Waterless Formulations

There are anhydrous soaps, shampoo soap bars, whipped butters and balms, even oil-based serums and humectant-based serum concepts. Generally, most waterless formulations increase the density of active ingredients in their formulations through the elimination of water. This higher concentration of active enhances the performances and reduces the amount of product needed to be used per dose, providing added value for skincare.

Safe dilution: Understanding the risk between concentrate and final product

The type of waterless formulations that have proven to be a challenge to develop are cleansing preparations in powdered form. Waterless cosmetics in powder form are often dry formulations that require added water from the end consumer for activation, while oil or wax based solid cosmetics are typically ready-to-use without the addition of water.

When creating powdered waterless products, there is a lot to consider. These types of formulations require reverse engineering and good application of science. The following needs to be taken into account:

• The end user;
• The means for which they will use the product;
• The concentrations they're expected to use or dilute the product.

But most importantly, you need to consider the warnings for the concentrate knowing that you will be considering the end product when the end user has diluted the concentrate to make a product. For example, a powdered shampoo — where the consumer adds their own water and shakes the powdered concentrate into the water to create a single-use shampoo product. In the concentrate to be sold, if there were 10 servings in the packet, then we may use 10% preservative, rather than 1% preservative — so that we can guarantee the consumers' final product is adequately preserved. This would come with PPE (wearing gloves when handling warnings) and any MSDS (Material Safety Data Sheet) cautions for the preservative in question. If we opt for 1% preservative for the concentrate, then we would have to communicate this and ensure that consumers don't keep their final concoction and brand their end result as "single use" items not to be kept.

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In the instance of "paper shampoo" — shampoo sheets that dissolve in water to create single use cleansing experiences — how can a chemist be sure that the paper formulation dissolves in a way that is sufficient and offers a good cleansing experiences that doesn't fail the customers' expectations of what is achievable in this format? A lot of applied science needs to be used effectively to ensure that the anhydrous surfactants have a good weight of actives and that the rheological modifiers also seamlessly thicken the added water, simultaneously allowing for the paper substrate to dissolve.

There's so much more risk management of the final outcomes of use in these types of products. Powdered cleansing shampoos, toothpaste pills or tablet mouthwashes, the options seem endless. But we need to remember that we're formulating based on the dosage the consumer is expected to use. We're either controlling dosage by offering single use formats, i.e. sheet conditioners or cleansing tablets. Or, we're controlling the dosage by offering explicit warnings and directions for use to ensure proper use of the formulation in a safe manner.

Communicating with the customer via marketing and packaging is key. When we don't manage the risks, as with all products, and don't formulate with meticulous detail and good science, the cons outweigh the pros — which both are very fine lines. What was once perceived as higher concentrations giving enhanced performance, will quickly become skin sensitizing and dangerous. There is a balancing act and need for a good scientific approach.

Overcoming these challenges is worthwhile to produce products that reduce a brands' environmental impact, have longer shelf lives, whilst offering the consumer value and often provide enhanced product performance.

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