How Does it Feel?

When my colleagues and I are considering a new dermatological formulation, we focus on four areas: solubility, stability, sensory and delivery. We ensure that the API is at least partially soluble in the formulation and stable physically and chemically. We also consider whether the patient will actually apply the formulation and ensure that the active pharmaceutical ingredient (API) can reach the required target.

The pharmaceutical industry puts a huge amount of resource into the solubility, stability and delivery aspects of derma formulation, but the sensory aspect is something that is largely overlooked, if not ignored altogether. Is it really right to leave the aesthetics of a formulation to an afterthought?

This point was very well made by a professor of dermatology, Steven Feldman, who said “I think vehicle effects on delivery through the stratum corneum are less important than the fact that the patient actually puts the medicine on” (1). It’s an irrefutable fact that no drug is bioavailable when it stays in the container.

I’m not saying that the formulation aesthetics should be considered more important than bioavailability, or indeed other aspects of designing a new formulation, but that all factors need to be taken into consideration to design a truly successful treatment. I have frequently heard the comment, “If the patient has the disease they will use the treatment”, and for very severe conditions I imagine this is quite true. However, for milder conditions and many over-the-counter formulations I think this assumption is made with the mindset of a scientist. As a scientist, I know that the activity of the API often takes time; I know that I must keep applying the product for the correct number of times per day to get results. But do all users think like this? Do patients always finish their course of antibiotics, even after they feel better? Does the patient always apply the ointment three times a day? I’m less than convinced.

Compliance or concordance is essential to create a successful treatment, but there are a lot of different facets required to achieve it. Where do we start? I think that one area that the world of healthcare can learn from is cosmetics. Cosmetics are based around creating a consumer belief in the product. I’m certainly not proposing that a good cosmetic story replaces the rigorous science needed to develop a topical pharma product, but we should consider some of the psychology used.

I started my formulation career in cosmetics. In those days, I would formulate skincare products with three aspects in mind. Firstly, make sure the formulation you offer does not feel horrible; finding something that the majority of people would agree that they strongly like is difficult, and yet most people readily agree on what feels unpleasant to apply. Secondly, make the consumer believe there is an improvement in the first few minutes of application. Thirdly, make sure the formulation meets the consumer expectations in the long term.

The best example of this is an anti-aging cream. For daywear, you develop a light formulation that quickly absorbs into the skin, and for night-time use you create a more substantial-feeling product. Ingredients are added to the formulation to give what are referred to as 'instant effects'; for anti-aging creams these will give the appearance of smoother skin. This element is really important as without this immediate ‘evidence’ of an effect it’s unlikely that the user will stick with the formulation. Maintaining use of the product actually allows the emollients and anti-aging actives to achieve their long-term effect.

I’m not suggesting that healthcare formulations require instant effects but there is something to be taken from the idea. When starting to formulate, take some time to consider the aesthetics. Can you really expect someone to apply a heavy, greasy formulation made of petrolatum or high-molecular-weight PEG twice a day? Does the formulation convince the user that it’s doing some good? Can you expect a patient with sore and broken skin to apply and rub in a thick, paste-like formulation?

I believe pharmaceutical formulators need to consider a wider selection of ingredients, moving away from the trusted topical formulations used for decades, and formulate products with cosmetically acceptable aesthetics. Only then will a patient happily use the product every day as instructed, and we can move closer to achieving complete concordance.