The answer to topical adherence? 23rd October 2023
By Lies d’Olieslager, European Technical Product Manager, IMCD Pharmaceuticals.
Therapy adherence is key to achieving the therapeutic goals of a medical treatment.
The WHO defines adherence to treatment as ‘the extent to which a person’s behavior – taking medication, following a diet and/or executing lifestyle changes – corresponds with agreed recommendations from a health care provider’. Patient adherence to therapy is a well-known challenge in dermatology, especially for the main topical diseases like atopic dermatitis, psoriasis and acne that require long-term treatment. Additionally, most of these patients are children, which add even more challenges with therapy. Sometimes, poor adherence can even be confused with poor treatment response, which may lead to the prescription of more powerful and dangerous systemic medications causing unwanted (and avoidable) side-effects.
Increasing therapy compliance will lead to better therapy outcome and disease control, avoid unnecessary treatment, prevent complications, improve quality of life and decrease the treatment costs for the patient.
Topical therapy is often complex and requires significant patient involvement, as topical formulations often need to be applied multiple times per day for a long, sometimes even life-long, period of time.
However, one of the key factors driving patient compliance is the patient-friendliness of topical formulations. For topicals, this aspect is directly linked to the cosmetic and galenic properties of the formulation, like the smell and the appearance, the (after) feeling on the skin (greasy, tacky, shiny), but also the time needed for the application, as well as convenience of application (spreadability, absorption time, etc).
The vehicle used is mainly driving these aesthetic parameters, while the formulation type will influence the convenience and application time. Formulators have the option to use novel, sensory-enhanced excipients (like for example silicones or special grade mineral oils) or develop different dosage forms (sprays, films, foams, etc) or a combination of both to increase adherence. It is becoming increasingly clear that changing from more traditional formulations like creams and ointments to more novel ones like sprays, films, foams and hydrogels, as well as the use of sensory-enhanced excipients will increase patient adherence significantly. Patients find these types of formulations easier to apply, to use and to spread, more comfortable to use under make-up and/or cosmetics, and they are suitable for use on multiple body areas, and stain-free.
One important factor that should not be neglected is the fact that the type of vehicle can control or influence the penetration of the drug into the skin and therefore the choice of vehicle can significantly affect medication efficacy. It’s up to the formulator to balance efficiency and cosmetic appearance. More and more excipient suppliers are focusing not only on excipients, but also these novel dosage forms.
Foam formulations are one of the new trending dosage forms used for topicals. They are an attractive, elegant and promising delivery system as they are easier to apply and have better spreadability than other topical dosage forms. Ease of spreading reduces the need to apply pressure or maintain prolonged contact with the sensitive diseased area. Unlike low viscosity solutions, which can flow and drip away from the application site, foams tend to remain in the area where they are applied.
Despite all these benefits, there are only a limited number of topical foam formulations on the market. This is probably due to the need for very specific excipients and the related cost.
However, there are other solutions available for formulators. Developing a sprayable formulation (lotion or solution) could be another patient-friendly alternative. Especially if combined with the use of novel ingredients like mucoadhesive excipients (carbomers or carrageenan) and novel sensory-enhanced excipients.
In the end, there are novel excipients that can help formulators achieve a patient-friendly and often improved topical formulation, and there are novel dosage forms that can improve compliance and effectiveness. Regulators are trying to speed up the regulatory processes and the acceptance frame for both – it’s up to the drug manufacturers and formulators to start developing for the modern patient.
Innovation is the future and novel excipients are the way towards the creation of modern user-friendly and effective topical formulations.